Zoom lens

ABSTRACT

The invention relates to a zoom lens system which is compatible with a TTL optical finder having a diagonal field angle of at least 70° at the wide-angle end and about 7 to 10 magnifications and is fast as represented by an F-number of about 2.8 at the wide-angle end. The zoom lens system comprises a first lens group G 1  which is movable along its optical axis during zooming and has positive refracting power, a second lens group G 2  which moves toward the image side along the optical axis during zooming from the wide-angle end to the telephoto end and has negative refracting power and rear lens groups G 3  to G 6  having at least two spacings variable during zooming. In particular, the focal length f 1  of the first lens group G 1  should meet 6&lt;f 1 /L&lt;20 where L is the diagonal length of an effective image pickup surface I located in the vicinity of an image-formation plane.

BACKGROUND OF THE INVENTION

[0001] This application claims benefit of Japanese Patent Application No. 2000-250577 filed in Japan on 8.22.200, the contents of which are incorporated by this reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to a zoom lens, and more particularly to a high-aperture-ratio, high zoom-ratio zoom lens system including a wide-angle zone which has a phototaking field angle of at least 700 suitable for cameras in general, and video cameras or digital cameras in particular.

[0003] In recent years, attention has been paid on digital cameras (electronic cameras) which are potential next-generation cameras superseding silver-salt 135 mm film (usually called Leica size) cameras. For digital cameras for general users, single-focus lenses having a diagonal field angle of about 600 or zoom lenses of about 3 magnifications using the same at wide-angle ends go mainstream. For high-class users, on the other hand, zoom lenses must be further extended to the wide-angle or telephoto end, and be compatible with TTL optical finders as well. As a matter of course, such zoom lenses are required to have ever higher performance. For zoom lenses having a diagonal field angle of about 750 at the wide-angle end and about 7 to 10 magnifications and compatible with TTL optical finders, some are now commercially available for the aforesaid silver-salt 135 mm film cameras. However, wide-angle, high-zoom-ratio zoom lenses, which are well suitable for image-pickup formats considerably smaller in size than the film camera formats and are fast as expressed by an F-number of about 2.0 to 2.8 at the wide-angle end, are little known except those for TV cameras and other commercial purposes.

SUMMARY OF THE INVENTION

[0004] The state of the art being like this, an object of the present invention is to provide a wide-angle, high-zoom-ratio zoom lens, and especially a zoom lens system which is compatible with a TTL optical finder having a diagonal field angle of at least 700 at the wide-angle end and about 7 to 10 magnifications, and is fast as well, as expressed by an F-number of about 2.0 to 2.8 at the wide-angle end.

[0005] To achieve this object, the present invention basically provides

[0006] a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups or, alternatively,

[0007] a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and has negative refracting power, and a rear group which is located subsequent to the second lens group and has at least two spacings variable during zooming.

[0008] Such constructions are favorable for achieving high zoom ratios while various aberrations are minimized. The present invention having such basic constructions has the following characteristic features.

[0009] According to the first embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and a rear lens group having at least two spacings variable during zooming, wherein a focal length f₁ of the first lens group satisfies the following condition (1):

6<f ₁ /L<20  (1)

[0010] where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.

[0011] When the lower limit of 6 to condition (1) is not reached, spherical aberrations remain under-corrected at the telephoto end. When the upper limit to 20 is exceeded, the amount of zooming movement of the movable groups increases, and so the overall size of the zoom lens system tends to increase.

[0012] More preferably, condition (1) should be reduced to

6.5<f ₁ /L<16  (1′)

[0013] Most preferably, condition (1) should be reduced to

7<f ₁ /L<12  (1″)

[0014] According to the second embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and a rear lens group having at least two movable subgroups or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and a rear lens group having at least two spacings variable during zooming, wherein a focal length f₁ of the first lens group and anomalous dispersion Δθ_(gF) of a medium of at least one positive lens in the first lens group satisfy the following conditions:

6<f ₁ /L<20  (1)

0.015<Δθ_(gF)<0.1  (2)

[0015] where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.

[0016] It is here noted that the anomalous dispersion Δθ_(gF) of each medium (vitreous material) is defined by

θ_(gF) A _(gF) +B _(gF)·ν_(d)+Δθ_(gF)

[0017] with the proviso that θ_(gF)=(n_(g)−n_(F))/(n_(F)−n_(c)) and ν_(d)=(n_(d)−1)/(n_(F)−n_(c)) wherein n_(d), n_(F), n_(c) and n_(g) are refractive indices with respect to d-line, F-line, C-line and g-line, respectively, and A_(gF) and B_(gF) are each a linear coefficient determined by two vitreous material types represented by glass code 511605 (available under the trade name of NSL7, Ohara Co., Ltd. with θ_(gF)=0.5436 and ν_(d)=60.49) and glass code 620363 (available under the trade name of PBM2, Ohara Co., Ltd. with θ_(gF)=0.5828 and ν_(d)=36.26); that is, A_(gF) is 0.641462485 and B_(gF) is −0.001617829.

[0018] When the lower limit of 0.015 to condition (2) is not reached, short wavelength longitudinal chromatic aberrations remain under-corrected at the telephoto end, and so colors are likely to bleed out at the edges of a subject having a large luminance difference. Any inexpensive medium exceeding the upper limit of 0.1 is little available, and opposite chromatic aberrations occur above 0.1.

[0019] More preferably, conditions (2) and (3) should be reduced to

6.5<f ₁ /L<16  (1′)

0.020<Δθ_(gF)<0.08  (2′)

[0020] Most preferably, conditions (2) and (3) should be reduced to

7<f ₁ /L<12  (1″)

0.025<Δθ_(gF)<0.06  (2″)

[0021] According to the third embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to an image side of the second lens group, or three negative lens elements located nearest to an object side of the second lens group while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to the image side of the second lens group, with any one of surfaces in the second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of the first lens group from the wide-angled end to the telephoto end when the zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of the second lens group from the wide-angle end to the telephoto end when the zoom lens system is focused on an object point at infinity:

3<(Δz ₂ −Δz ₁)/L<9  (3)

[0022] where the movement of each lens group toward the image side is assumed to be positive and L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.

[0023] For zooming from the wide-angle end to the telephoto end, the second lens group is relatively moved away from the first lens group, as already explained. Especially for a high-zoom-ratio zoom lens system, there must be a space large enough for the movement of the second lens group because that amount of movement is large. This is particularly true as the field angle of the zoom lens system becomes wide. As a result, the diameter of the first lens group often becomes too large. When the upper limit of 9 to condition (3) is exceeded, the diameter of the first lens group becomes too large and so the size of the zoom lens system becomes large. When the lower limit of 3 is not reached, there is an increased load of zooming on the rear lens group, which may result in large fluctuations of spherical aberrations upon zooming.

[0024] More preferably, condition (3) should be reduced to

3.2<(Δz ₂ −Δz ₁)/L<8  (3′)

[0025] Most preferably, condition (3) should be reduced to

3.4<(Δz ₂ −Δz ₁)/L<7(3″)

[0026] When a zoom lens system has a wide-angle, high-zoom-ratio arrangement, the largest load is applied on the second lens group. In addition, even the magnitude of the diameter of the first lens group is determined by the power, amount of movement, and arrangement of the second lens group. In consideration of the diameter of the first lens group alone, it is favorable to locate the principal point of the second lens group as close to the object side as possible. Thus, it is preferable that the second lens group is constructed of a front subgroup having negative refracting power and a rear subgroup having positive refracting power. In this case, however, barrel distortion is likely to occur due to the wide-angle, high-zoom-ratio arrangement and difficulty is involved in making correction for astigmatism all over the zooming zone. These problems can substantially be eliminated if the second lens group is constructed of at least three negative lenses and a positive lens located nearest to the image side thereof, or three negative lenses located nearest to the object side thereof and a positive lens located on the image side, or a negative lens and two positive lenses located nearest to the image side thereof, with any one of the surfaces in the second lens group being defined by an aspheric surface.

[0027] When the number of lenses in the rear lens group is less than 6, severe conditions are added to correction of chromatic aberrations and spherical aberrations. When more than 11 lenses are used, on the other hand, the entire rear lens group becomes too thick to secure ample zooming space.

[0028] The rear lens group has a plurality of subgroups. In view of chromatic aberrations, spherical aberrations, coma and increased aperture, it is more preferable to construct the rear lens group of at least two subgroups having positive refracting power, wherein the subgroup located nearest to the image side thereof and having positive refracting power and the subgroup located nearest to the image side thereof and having positive refracting power are each composed of at least three lenses.

[0029] According to the fourth embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to an image side of the second lens group, or three negative lens elements located nearest to an object side of the second lens group while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to the image side of the second lens group, with any one of surfaces in the second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of the zoom lens system during zooming, a second lens group which moves toward an image side of the zoom lens system along the optical axis during zooming from a wide-angle end to a telephoto end of the zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of the first lens group from the wide-angle end to the telephoto end when the zoom lens system is focused on an object point at infinity and an amount of movement ΔZ₂ of the second lens group from the wide-angle end to the telephoto end when the zoom lens system is focused on an object point at infinity:

−1.0<(Δ_(z1)/Δ_(z2)<0.5 where Δ_(z2)>0  (4)

[0030] where the movement of each lens group toward the image side is assumed to be positive.

[0031] This is the condition for making a proper locus of an image point defined by a composite first-and-second lens group system upon zooming from the wide-angle end to the telephoto end. By this locus, the magnification-variable zone and focal length of the rear lens group are determined to some extent. When the upper limit of 0.5 to condition (4) is exceeded, the magnification of the rear lens group becomes low or the focal length of the rear lens group becomes long and, hence, the entire size of the zoom lens system tends to become large relative to the value of L. When the lower limit of −1.0 is not reached, on the contrary, the entire size of the zoom lens system becomes small relative to the value of L. However, when the value of L is small and the F-number is small, it is difficult to make correction for spherical aberrations and comas.

[0032] It is acceptable to meet condition (4) and condition (3) simultaneously.

[0033] More preferably, condition (4) should be reduced to

−0.9<(Δ_(z1)/Δ_(z2)<0.4 where Δ_(z2)>0  (4′)

[0034] Most preferably, condition (4) should be reduced to

−0.8<(Δ_(z1)/Δ_(z2)<0.3 where Δ_(z2)>0  (4″)

[0035] According to the fifth embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two spacings variable during zooming, wherein said first lens group moves toward said image side in a convex reciprocation locus and an amount of movement Δz_(1WM) of said first lens group from said wide-angle end to an intermediate focal length of said zoom lens system, given by f_(M)(={square root}{square root over ( )}(f_(W)·f_(T))), is positive where f_(W) is a composite focal length of said zoom lens system when focused at said wide-angle end on an object point at infinity and f_(T) is a composite focal length of said zoom lens system when focused at said telephoto end on an object point at infinity, with the proviso that the movement of said first lens group lens toward said image side is assumed to be positive and f_(M) is the geometric mean of f_(W) and f_(T). It is here noted that upon zooming from the wide-angle end to the telephoto end, the second lens group moves relatively away from the first lens group and the rear lens group moves in such a way that its principal point position goes off an image plane. It is also noted that the position of the image plane is kept constant.

[0036] When an electronic image pickup device or a viewing frame having a small value for L, the magnification of the rear lens group is particularly small or nearly one even at the telephoto end, because the ratio of the focal length of the first lens group to that of the zoom lens system becomes very large. At the same time, since the focal length of the rear lens group is longer than that of the second lens group, it is required that a locus of an image point defined by a composite first-and-second lens group system upon zooming from the wide-angle end to the telephoto end change considerably sharply toward the image side in the vicinity of the wide-angle end, and change considerably gently at the telephoto end. In other words, it is preferable that such a locus as mentioned above is taken by the first lens group.

[0037] According to the sixth embodiment of the present invention, there is a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two spacings variable during zooming, wherein said first lens group moves toward said image side in a convex reciprocation locus and only the aforesaid condition (4) or both conditions (3) and (4) are satisfied.

[0038] In this embodiment, too, the effects mentioned with reference to the fourth and fifth embodiments are obtainable.

[0039] According to the seventh embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming.

[0040] When a zoom lens system has a wide-angle, high-zoom-ratio arrangement, the largest load is applied on the second lens group. In addition, even the magnitude of the diameter of the first lens group is determined by the power, amount of movement, and arrangement of the second lens group. In consideration of the diameter of the first lens group alone, it is favorable to locate the principal point of the second lens group as close to the object side as possible. Thus, it is preferable to locate a positive lens nearest to the image side of the second lens group. In this case, however, barrel distortion is likely to occur due to the wide-angle, high-zoom-ratio arrangement and difficulty is involved in making correction for astigmatism all over the zooming zone. These problems can substantially be eliminated if the second lens group is constructed of at least three negative lenses, wherein at least one surface is formed by an aspheric surface. In particular, it is preferable that the aspheric surface is of such a shape that off and off the center of the aspheric surface, its divergence becomes weaker or its convergence becomes stronger as compared with its longitudinal curvature. Even when the second lens group is constructed of three negative lenses located nearest to the object side thereof with a positive lens located on the image side thereof or constructed of a negative lens with two positive lenses located nearest to the image side thereof, similar effects are obtainable as already mentioned.

[0041] Furthermore in this embodiment, the following conditions should preferably be satisfied with respect to a β_(2T)/β_(2W) ratio Δβ₂ where β_(2T) is the magnification of the second lens group at the telephoto end and β_(2W) is the magnification of the second lens group at the wide-angle end when the zoom lens system is focused on an object point at infinity and the focal length f₂ of the second lens group.

0.3<log (Δβ₂) /log (γ)<0.8  (5)

5<γ<15  (6)

[0042] Here γ is the zoom ratio of the zoom lens system from the wide-angle end to the telephoto end.

[0043] When a zoom lens system has a wide-angle, high-zoom-ratio arrangement, the largest load is applied on the second lens group, as already mentioned. In addition, even the magnitude of the diameter of the first lens group is determined by the power, amount of movement, and arrangement of the second lens group. It is thus preferable to allocate the zooming function to the rear lens group as much as possible. Condition (5) is provided to define the proportion of the zoom ratio of the second lens group all over the zooming zone. When the upper limit of 0.8 is exceed, the load of the zooming function on the second lens group becomes too large to make correction for the aforesaid off-axis aberrations and reduce the diameter of the first lens group. When the lower limit of 0.3 is not reached, on the contrary, the load of the zooming function on the rear lens group becomes too large and, hence, it is difficult to achieve large aperture because spherical aberrations, coma and so on become instable all over the zooming zone. Condition (6) represents the zoom ratio range wherein condition (5) is effective. Any departure from this range causes condition (5) to be ineffective. In other words, when the upper limit of 15 to condition (6) is exceeded, it is preferable to reduce the degree of allocation of the zooming function to the second lens group to below the lower limit to condition (5). When the lower limit of 5 is not reached, on the other hand, it is acceptable to increase the degree of allocation of the zooming function to the second lens group to greater than the upper limit to condition (5) because influences of aberrations diminish. However, any sufficient zoom ratio is not obtainable.

[0044] More preferably, the aforesaid conditions should be

0.35<log (Δβ₂)/log (γ)<0.65  (5′)

9<γ<15  (6′)

[0045] or

0.5<log (Δβ₂)/log (γ)<0.8  (5″)

5<γ<9  (6″)

[0046] According to the eighth embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming, wherein the following condition is satisfied with respect to the composite magnification β_(rW) of the rear lens group when the zoom lens system is focused at the wide-angle end on an object point at infinity.

−0.6<β_(rW)<−0.1  (7)

[0047] As already mentioned, when an image pickup device or a film viewing frame having a small value for L (the diagonal length of an effective image pickup surface) is used, the ratio of the focal length of the first lens group to that of the zoom lens system becomes very large. For instance, this is because the simple proportional coefficient multiple of an optical system for 135 mm format or APS format cannot be physically applied to mechanical construction or lens machining. For this reason, it is impossible to reduce the focal length of each lens group, and especially the composite focal length of the first and second lens groups. In other words, the magnification of the rear lens group must be smaller than that of an optical system for the aforesaid formats. When the lower limit of −0.6 to condition (7) is not reached, the focal length of the composite first-and-second lens group system tends to become short and, hence, the edge thickness, center thickness and air space of each lens tend to become extremely small. An attempt to secure these make the Petzval sum of the optical system negative and, at the same time, renders it difficult to secure off-axis aberrations such as distortion, astigmatism and coma all over the zooming zone. When the upper limit of −0.1 is exceeded, the lens system tends to become huge.

[0048] It is preferable that the aforesaid rear lens group is composed of at least three subgroups, each having a variable axial relative distance, and three such subgroups have positive, negative, and positive power in order from the object side of the rear lens group.

[0049] Alternatively, it is preferable that the rear lens group is composed of a plurality of subgroups, each having a variable axial relative distance, and all subgroups in the rear lens group have each at least one doublet component. Still alternatively, it is preferable that the rear lens group is composed of at least three subgroups, each having a variable axial relative distance and all subgroups in the rear lens group have each at least one doublet component.

[0050] It is more preferable that when 9<γ<15 (6′), −0.5<β_(rW)<−0.1 (7′), or when 5<γ<9 (6″), −0.6<β_(rW)<−0.2 (7″).

[0051] According to the ninth embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming, wherein focusing is effected by any one of subgroups located nearer to an image side of said rear lens group than a positive subgroup of subgroups having negative magnification, said positive subgroup located nearest to an object side of said rear lens group, and the following condition is satisfied with respect to a magnification β_(RRW) of said positive subgroup located nearest to the image side of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity:

−0.4<β_(RRW)<0.9  (8)

[0052] In the present invention, focusing is effected by moving a subgroup or subgroups in the rear lens group on the optical axis, and zooming is effected by the second lens group and the rear lens group. Actually, however, only the subgroup of a plurality of subgroups constituting the rear lens group, which subgroup has positive refracting power and negative magnification and is located nearest to the object side of the rear lens group, contributes to zooming. Other subgroups are designed to have magnifications far away from −1, so that focusing can be done by one or more of the subgroups. It is particularly preferable to effect focusing with a positive subgroup located nearest to the image side of the rear lens group, because there are little fluctuations of aberrations with focusing. Condition (8) is provided to define the magnification β_(RRW) of the positive subgroup located nearest to the image side of the rear lens group. Falling below the lower limit of −0.4 is not preferable because of increased fluctuations of the paraxial amount and the amount of aberrations. Exceeding the upper limit of 0.9 is again not preferable because the amount of movement of the focusing subgroup becomes too large and so this subgroup tends to interfere with the adjacent subgroup before focusing is achieved from an object point at infinity to a close-up object point.

[0053] It is preferable that focusing is effected by the positive subgroup located nearest to the image side of the rear lens group and/or a negative subgroup located on the object side of the rear lens group, because fluctuations of aberrations with focusing can be so reduced that proper focusing and proper sensitivity can be obtained.

[0054] More preferably, condition (8) should be reduced to

−0.3<β_(RRW)<0.8  (8′)

[0055] Most preferably, condition (8) should be reduced to

−0.2<β_(RRW)<0.7  (8″)

[0056] According to the tenth embodiment of the present invention, there is provided a a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having at least two spacings variable during zooming, wherein the following conditions are satisfied with respect to an amount of movement Δ_(zRF) of a subgroup of said subgroups in said rear lens group, said subgroup having positive refracting power and located nearest to an object side of said rear lens group, from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δ_(zRR) of a positive subgroup located nearest to an image side of said rear lens group when said zoom lens system is focused on an object point at infinity:

−0.4<Δ_(zRR)/Δ_(zRF)<0.8  (9)

0.3<|Δ_(zRF) |/L<4.0  (10)

[0057] where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.

[0058] Of the subgroups constituting the rear lens group, the positive subgroup located nearest to the object side of the rear lens group contributes actually to zooming. Consequently, this subgroup moves monotonously toward the object side of the zoom lens system from the wide-angle end to the telephoto end thereof. Other subgroups have magnifications far away from −1, and move or act substantially to make correction for displacements of focusing positions due to zooming and aberrations. On the other hand, as the positive subgroup located nearest to the image side of the rear lens group moves toward the object side of the zoom lens system than required, the position of an exit pupil comes close to the image plane. For this reason, when an electronic image pickup device is used, shading is likely to occur. When the upper limit of 0.8 to condition (9) is exceeded, the exit pupil comes close to the image plane on the telephoto side, and so the angle of light rays incident on the perimeter of a screen becomes too large. When the lower limit of −0.4 is not reached, the total thickness of the rear lens group increases and so the overall size of the optical system becomes large. When the upper limit of 4.0 to condition (10) is exceeded, it is likely that the overall length of the optical system becomes long or fluctuations of aberrations with zooming become noticeable. When the lower limit of 0.3 is not reached, the diameter of the first lens group is likely to become large. These are true even when at least one subgroup is placed midway between the aforesaid two positive subgroups. Especially when that subgroup is a negative one, it is preferable to satisfy

−2<Δ_(zRN) /L<1  ( 11)

[0059] Here Δ_(zRN) is the amount of movement of the negative subgroup from the wide-angle end to the telephoto end when the zoom lens system is focused on an object point at infinity. When the lower limit of −2 to this condition is not reached, the total thickness of the rear lens group increase and so the overall size of the optical system becomes large. When the upper limit of 1 is exceeded, it is likely that the subgroups interfere during focusing on a nearby object point at the telephoto end. This holds true even when a negative subgroup is located on the object side with respect to the aforesaid positive subgroups and on the image side with respect to the second lens group.

[0060] More preferably, the following conditions should be satisfied independently or simultaneously.

−0.3<Δ_(zRR)/Δ_(zRF)<0.7  (9′)

0.5<|Δ_(zRF) |/L<3.5  (10′)

−1.5<Δ_(zRN) /L<0.7  (11′)

[0061] Most preferably, the following conditions should be satisfied independently or simultaneously.

−0.2<Δ_(zRR)/Δ_(zRF)<0.6  (9″)

0.7<|Δ_(zRF) |/L<3.0  (10″)

−1<Δ_(zRN) /L<0.5  (11″)

[0062] It is also preferable that the positive subgroup located nearest to the object side of the rear lens group has negative magnification in view of its contribution to zooming.

[0063] According to the eleventh embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lenses inclusive, said rear lens group comprising a subgroup having positive refracting power and negative magnification and a positive subgroup located nearest to an image side of said rear lens group which vary in relative positions thereof during zooming, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having a plurality of subgroups, said rear lens group comprising a subgroup having positive refracting power and negative magnification and a positive subgroup located nearest to an image side of said rear lens group with a negative subgroup located between said two positive subgroup, while said three subgroup vary in relative positions thereof during zooming, wherein said two positive subgroups have each at least one doublet component, at least one aspheric surface and at least one lens formed of a vitreous material with ν>80 where ν is an Abbe constant. Since the chromatic aberrations, spherical aberrations and comas of each lens group are in good condition, satisfactory images can be obtained from the wide-angle end to the telephoto end. It is here preferable that the negative subgroup located midway between the two positive subgroups includes a doublet.

[0064] According to the twelfth embodiment of the present invention, there is provided a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable positive subgroups and comprising a total of 7 to 11 lenses inclusive, or a zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having at least three spacings variable during zooming, wherein a subgroup located nearest to an object side of said rear lens group has negative refracting power.

[0065] In the zoom lens system according to the present invention, when a finder optical path-splitting member is inserted between the subgroup located nearest to the image side of the rear lens group and the image lance, a long back focus is needed. In other words, an attempt to forcibly ample back focus makes the Petzval sum of the zoom lens system likely to become negative. It is thus preferable that a negative lens subgroup is located nearest to the object side of the rear lens group. It is here noted that the negative subgroup located nearest to the object side of the rear lens group may be made up of one lens component or fixed in the vicinity of a stop. By the “lens component” used herein is intended a lens with no air separation between the object-side surface and the image-side surface thereof, which are in contact with air, or specifically a single lens or a doublet.

[0066] It is preferable that a negative subgroup and an aperture stop are located on the object side with respect to the two positive subgroup and on the image side with respect to the second lens group, with a spacing being at most three times as large as the thickness of that negative subgroup on the optical axis of the zoom lens system.

[0067] When a subgroup having negative refracting power is located nearest to the object side of the rear lens group, it is preferable to construct the rear lens group of seven or more lenses in all.

[0068] In the eleventh embodiment of the invention, it is preferable that the zoom lens system comprises, in order from an object side thereof, a first lens group which is movable along an optical axis thereof during zooming and positive refracting power, a second lens group which is movable along the optical axis and has negative refracting power, and a rear lens group located subsequent thereto and having variable refracting power, while at least one of the following three conditions is satisfied.

2.0<F _(BW) /f _(W)<5.0  (12)

1.4<F _(W)<3.5  (13)

2<ENP/L<5  (14)

[0069] Here F_(BW) is the back focus (calculated on an air basis) when the zoom lens system is focused at the wide-angle end on an object point at infinity, F_(W) is the minimum F-number when the zoom lens system is focused at the wide-angle end on an object point at infinity, and ENP is the position of an entrance pupil at the wide-angle end.

[0070] The present invention is found to be effective for lens systems that satisfy one of these conditions. In particular, the present invention is best suited for image pickup systems using electronic image pickup devices. Especially when the present invention is applied to an image-formation optical system for phototaking systems (cameras, video movies, etc.) including a high-pixel image pickup device with a pixel interval a represented by

1.0×10⁻⁴ ×L<a<6.0×10⁻⁴ ×L  (mm)

[0071] it is possible to achieve an image pickup system making effective use of the image quality of a high-pixel arrangement.

[0072] Two or more of the conditions mentioned above with reference to the present zoom lens system should preferably be satisfied simultaneously. More preferably, two or more of the requirements for the present invention should be satisfied at the same time. The more the number of the requirements met, the better the results are.

[0073] In each of the embodiments of the present invention, it is preferable that the second lens group comprises at least three negative lenses while a positive lens is located nearest to said image side, or three negative lenses located nearest to said object side while a positive lens is located on said image side or a negative lens while two positive lenses are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface. When the rear lens group has at least two spacings variable during zooming, it is preferable that the rear lens group is made up of 7 to 11 lenses in all. More preferably, the rear lens group is made up of 7 to 9 lenses inclusive in all while two aspheric surfaces are used, because an arrangement favorable in view of size is achievable while high image-formation capability is maintained.

[0074] By the combined use of two or more of the aforesaid embodiments, it is possible to obtain ever higher effects.

[0075] Still other objects and advantages of the invention will be in part be obvious and will in part be apparent from the specification.

[0076] The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0077]FIG. 1 is a sectional view for the lens arrangement of Example 1 of the zoom lens system according to the invention when focused on an object point at infinity.

[0078]FIG. 2 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 2 of the zoom lens system.

[0079]FIG. 3 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 3 of the zoom lens system.

[0080]FIG. 4 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 4 of the zoom lens system.

[0081]FIG. 5 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 5 of the zoom lens system.

[0082]FIG. 6 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 6 of the zoom lens system.

[0083]FIG. 7 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 7 of the zoom lens system.

[0084]FIG. 8 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 8 of the zoom lens system.

[0085]FIG. 9 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 9 of the zoom lens system.

[0086]FIG. 10 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 10 of the zoom lens system.

[0087]FIG. 11 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 11 of the zoom lens system.

[0088]FIG. 12 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 12 of the zoom lens system.

[0089]FIG. 13 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 13 of the zoom lens system.

[0090]FIG. 14 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 14 of the zoom lens system.

[0091]FIG. 15 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 15 of the zoom lens system.

[0092]FIG. 16 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 16 of the zoom lens system.

[0093]FIG. 17 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 17 of the zoom lens system.

[0094]FIG. 18 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 18 of the zoom lens system.

[0095]FIG. 19 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 19 of the zoom lens system.

[0096]FIG. 20 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 20 of the zoom lens system.

[0097]FIG. 21 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 21 of the zoom lens system.

[0098]FIG. 22 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 22 of the zoom lens system.

[0099]FIG. 23 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 23 of the zoom lens system.

[0100]FIG. 24 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 24 of the zoom lens system.

[0101]FIG. 25 is a sectional view, similar to FIG. 1, of the lens arrangement of Example 25 of the zoom lens system.

[0102] FIGS. 26(a), 26(b) and 26(c) are aberration diagrams for Example 1 when focused on an object point at infinity.

[0103] FIGS. 27(a), 27(b) and 27(c) are aberration diagrams for Example 2 when focused on an object point at infinity.

[0104] FIGS. 28(a), 28(b) and 28(c) are aberration diagrams for Example 3 when focused on an object point at infinity.

[0105] FIGS. 29(a), 29(b) and 29(c) are aberration diagrams for Example 4 when focused on an object point at infinity.

[0106] FIGS. 30(a), 30(b) and 30(c) are aberration diagrams for Example 5 when focused on an object point at infinity.

[0107] FIGS. 31(a), 31(b) and 31(c) are aberration diagrams for Example 6 when focused on an object point at infinity.

[0108] FIGS. 32(a), 32(b) and 32(c) are aberration diagrams for Example 7 when focused on an object point at infinity.

[0109] FIGS. 33(a), 33(b) and 33(c) are aberration diagrams for Example 8 when focused on an object point at infinity.

[0110] FIGS. 34(a), 34(b) and 34(c) are aberration diagrams for Example 9 when focused on an object point at infinity.

[0111] FIGS. 35(a), 35(b) and 35(c) are aberration diagrams for Example 10 when focused on an object point at infinity.

[0112] FIGS. 36(a), 36(b) and 36(c) are aberration diagrams for Example 11 when focused on an object point at infinity.

[0113] FIGS. 37(a), 37(b) and 37(c) are aberration diagrams for Example 12 when focused on an object point at infinity.

[0114] FIGS. 38(a), 38(b) and 38(c) are aberration diagrams for Example 13 when focused on an object point at infinity.

[0115] FIGS. 39(a), 39(b) and 39(c) are aberration diagrams for Example 14 when focused on an object point at infinity.

[0116] FIGS. 40(a), 40(b) and 40(c) are aberration diagrams for Example 15 when focused on an object point at infinity.

[0117] FIGS. 41(a), 41(b) and 41(c) are aberration diagrams for Example 16 when focused on an object point at infinity.

[0118] FIGS. 42(a), 42(b) and 42(c) are aberration diagrams for Example 17 when focused on an object point at infinity.

[0119] FIGS. 43(a), 43(b) and 43(c) are aberration diagrams for Example 18 when focused on an object point at infinity.

[0120] FIGS. 44(a), 44(b) and 44(c) are aberration diagrams for Example 19 when focused on an object point at infinity.

[0121] FIGS. 45(a), 45 (b) and 45 (c) are aberration diagrams for Example 20 when focused on an object point at infinity.

[0122] FIGS. 46(a), 46(b) and 46(c) are aberration diagrams for Example 21 when focused on an object point at infinity.

[0123] FIGS. 47(a), 47(b) and 47(c) are aberration diagrams for Example 22 when focused on an object point at infinity.

[0124] FIGS. 48(a), 48(b) and 48(c) are aberration diagrams for Example 23 when focused on an object point at infinity.

[0125] FIGS. 49(a), 49(b) and 49(c) are aberration diagrams for Example 24 when focused on an object point at infinity.

[0126] FIGS. 50(a), 50(b) and 50(c) are aberration diagrams for Example 25 when focused on an object point at infinity.

[0127]FIG. 51 is illustrative of the diagonal length of an effective image pickup surface for phototaking on an image pickup device.

[0128]FIG. 52 is illustrative of the diagonal length of an effective image pickup surface for phototaking on a phototaking film.

[0129]FIG. 53 is a front perspective view illustrative of the outside shape of a digital camera with the inventive zoom lens built therein.

[0130]FIG. 54 is a rear perspective view of the digital camera.

[0131]FIG. 55 is a sectional view of the FIG. 53 digital camera.

[0132]FIG. 56 is a conceptual illustration of a single-lens reflex camera's objective optical system with the inventive zoom lens incorporated therein.

[0133]FIG. 57 is a front perspective view illustrative of an uncovered personal computer in which the inventive zoom lens is incorporated as an objective optical system.

[0134]FIG. 58 is a sectional view of a phototaking optical system for a personal computer.

[0135]FIG. 59 is a sectional view of the FIG. 57 state.

[0136] FIGS. 60(a), 60(b) and 60(c) are a front and a side view of a portable telephone in which the inventive zoom lens is incorporated as an objective optical system and a sectional view of a phototaking optical system therefore.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0137] Set out below are Examples 1 to 25 of the zoom lens system according to the present invention. FIGS. 1 to 25 are sectional views illustrative of the lens arrangements of these examples when focused on an object point at infinity. Throughout the drawings, the first, second, third, fourth, fifth and sixth lens groups are shown at G1, G2, G3, G4, G5 and G6, respectively. A plane-parallel plate group comprising a finder optical path-splitting prism (a plane-parallel plate), an optical low-pass filter with an infrared cutting coat applied thereon and a cover glass for an electronic image pickup device such as a CCD is shown at P and an image plane at I. The plane-parallel plate group P is fixedly located between the final lens group and the image plane I. In FIGS. 1 to 25, the locus of movement of each lens group from the wide-angle end to the telephoto end is schematically depicted by an arrow. Numerical data on each example will be enumerated below.

[0138] As shown in FIG. 1, the zoom lens system of Example 1 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end when the system is focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocating locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 remains fixed with an aperture stop integrated therewith on the image side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the image side, and the sixth lens group G6 moves toward the object side in a convex reciprocating locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow, and reaches the telephoto end where it is located somewhat nearer to the image side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, for focusing at 0.3 m from an infinite object distance at the wide-angle end, on the one hand, the sixth lens group G6 moves toward the object side in such a way that the spacing between the fifth lens group G5 and the sixth lens group G6 changes from 8.26323 mm to 8.10753 mm. For focusing at 1.284 m (with a magnification of {fraction (1/20)}) from an infinite object distance at the telephoto end, on the other hand, the sixth lens group G6 moves toward the object side in such a way that the spacing between the fifth lens group G5 and the sixth lens group G6 changes from 5.08574 mm to 1.45116 mm.

[0139] In Example 1, the first lens group G1 is made up of a negative meniscus lens convex on the object side thereof, a double-convex lens and a positive meniscus lens convex on the object side thereof, the second lens group G2 is made up of a double-concave lens, a double-concave lens with an object-side surface thereof provided with a thin resin layer, thereby making this surface aspheric, and a doublet consisting of a negative meniscus lens convex on the image side thereof and a positive meniscus lens convex on the image side thereof, the third lens group G3 is made up of a negative meniscus lens convex on the image side thereof and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on the object side thereof and a double-convex lens, the fifth lens group G5 is made up of a double-concave lens and a positive meniscus lens convex on the object side thereof, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on the image side thereof. Three aspheric surfaces are used, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0140] As shown in FIG. 2, the zoom lens system of Example 2 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end when the zoom lens system is focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 remains fixed with an aperture stop integrated therewith on the image side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the image side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then somewhat wide, and reaches the telephoto end where it is located somewhat nearer to the image side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.7998 mm and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 2.2730 mm.

[0141] In Example 2, the first lens group G1 is made up of two lenses, i.e., a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a double-concave lens, a double-concave lens with an image-side surface thereof provided with a thin resin layer, thereby making that surface aspheric and a doublet consisting of a negative meniscus lens convex on its mage side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a positive meniscus lens convex on its image side and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the image-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0142] As shown in FIG. 3, the zoom lens system of Example 3 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end where the system is focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 remains fixed with an aperture stop integrated therewith on its image side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located somewhat nearer to the image side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then somewhat wide, and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.6726 mm and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 3.1112 mm.

[0143] In Example 3, the first lens group G1 is made up of two lenses, i.e., a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a positive meniscus lens convex on its object side with an image-side surface thereof provided with a thin resin layer, thereby making that surface aspheric, and a negative meniscus lens convex on its object side, the third lens group G3 is made up of a negative meniscus lens convex on its object side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the image-side resin layer surface of the positive meniscus lens in the second lens group G2, said lens convex on its object side, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0144] As shown in FIG. 4, the zoom lens system of Example 4 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power, a fourth lens group G4 having negative refracting power and a fifth lens group G5 having positive refracting. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end, and the fifth lens group G5 moves toward the object side in a convex reciprocation locus while the spacing between the fourth lens group G4 and the fifth lens group G5 becomes wide and then somewhat narrow, and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the fifth lens group G5 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 3.0843 mm and when focused on a nearby subject at the telephoto end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 2.2572 mm.

[0145] In Example 4, the first lens group G1 is made up of two lenses, i.e., a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens and a doublet consisting of a positive meniscus lens convex on its image side and a double-concave lens and a double-convex lens, the third lens group G3, with the fixed aperture stop located between the second lens group G2 and the third lens group G3, is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side, the fourth lens group G4 is made up of a doublet consisting of a positive meniscus lens convex on its image side and a double-concave lens, and the fifth lens group G5 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the object-side surface of the doublet in the second lens group G2, one for the object-side surface of the double-convex lens in the third lens group G3 and one for the object-side surface of the double-convex lens in the fifth lens group G5.

[0146] As shown in FIG. 5, the zoom lens system of Example 5 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power, a fourth lens group G4 having negative refracting power and a fifth lens group G5 having positive refracting. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end, and the fifth lens group G5 moves toward the object side while the spacing between the fourth lens group G4 and the fifth lens group G5 becomes wide and then somewhat narrow. For focusing on a nearby subject, the fifth lens group G5 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 4.2063 mm and when focused on a nearby subject at the telephoto end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 2.006 mm.

[0147] In Example 5, the first lens group G1 is made up of two lenses, i.e., a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a doublet consisting of a positive meniscus lens convex on its image side and a double-concave lens and a double-convex lens. The third lens group G3, with the fixed stop located between the second lens group G2 and the third lens group G3, is made up of a double-convex lens and a negative meniscus lens convex on its image side, the fourth lens group G4 is made up of a doublet consisting of a positive meniscus lens convex on its image side and a double-concave lens, and the fifth lens group G5 is made up of a doublet consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, a double convex lens and a positive meniscus lens convex on its object side. Three aspheric surfaces are used, one for the object-side surface of the doublet in the second lens group G2, one for the object-side surface of the double-convex lens in the third lens group G3 and one for the image-side surface of the double-convex lens in the fifth lens group G5.

[0148] As shown in FIG. 6, the zoom lens system of Example 6 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end of the zoom lens system where it is located nearer to the object side than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which is integrally provided with an aperture stop on its image side, moves toward the image side while the spacing between the second lens group G2 and the third lens group G3 becomes narrow, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the image side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow, and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the system. More specifically, when the system is focused on a nearby substance at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.9681 mm and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 1.7655 mm.

[0149] In Example 6, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a double-concave lens, a double-concave lens with an object-side surface thereof provided with a thin resin layer, thereby making that surface aspheric, and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0150] As shown in FIG. 7, the zoom lens system of Example 7 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which is integrally provided with an aperture stop on its image side, moves toward the image side while the spacing between the second lens group G2 and the third lens group G3 becomes narrow, the fourth lens group G4 moves toward the object side, and the fifth lens group G5 moves together with the sixth lens group G6 in a convex reciprocation locus and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.4249 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 3.9201 mm.

[0151] In Example 7, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens with an object-side surface thereof provided with a thin resin layer thereby making that surface aspheric, and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a double-concave lens and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a positive meniscus lens convex on its image side and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0152] As shown in FIG. 7, the zoom lens system of Example 7 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located on the object side of the system with respect to the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which is integrally provided with an aperture stop on its image side, moves toward the image side while the spacing between the second lens group G2 and the third lens group G3 becomes narrow, the fourth lens group G4 moves toward the object side, and the fifth lens group G5 moves together with the sixth lens group G6 in a convex reciprocation locus and reaches the telephoto end where it is located somewhat on the object side with respect to the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.4249 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 3.9201 mm.

[0153] In Example 7, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens with an object-side surface thereof provided with a thin resin layer thereby making that surface aspheric, and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a double-concave lens and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a positive meniscus lens convex on its image side and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0154] As shown in FIG. 8, the zoom lens system of Example 8 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located neater to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 is integrally provided with an aperture stop on its object side and remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 remains fixed, and the sixth lens group G6 moves toward the object side. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 8.5198 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 1.3741 mm.

[0155] In Example 8, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a double-concave lens, a double-concave lens with an object-side surface therein provided with a thin resin layer thereby making that surface aspheric, and a doublet consisting of a double-concave lens and a double-convex lens, the third lens group G3 is made up of a stop and a negative meniscus lens convex on its image side, the fourth lens group G4 is made up of a positive meniscus lens convex on its object side and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0156] As shown in FIG. 9, the zoom lens system of Example 9 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power and a fourth lens group G4 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the system when focused on an object point at infinity, the first lens group G1 moves to the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, and the fourth lens group G4 moves toward the object side while the spacing between the third lens group G3 and the fourth lens group G4 becomes wide. For focusing on a nearby subject, the fourth lens group G4 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the third lens group G3 and the fourth lens group G4 is set at 1.3397 mm, and when focused on a nearby subject at the telephoto end, the spacing between the third lens group G3 and the fourth lens group G4 is set at 15.0854 mm.

[0157] In Example 9, the first lens group G1 is made of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens with an image-side surface thereof provided with a thin resin layer thereby making that surface aspheric, and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the third lens group G3, with the fixed stop located between the second lens group G2 and the third lens group G3, is made up of a positive meniscus lens convex on its object side and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, and the fourth lens group G4 is made up of a doublet consisting of a double-convex lens and a double-concave lens, a positive meniscus lens convex on its image side and a doublet consisting of a double-convex lens and a double-concave lens. Three aspheric surfaces are provided, one for the image-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the positive meniscus lens in the third lens group G3 and one for the object-side surface of the positive meniscus lens in the fourth lens group G4.

[0158] As shown in FIG. 10, the zoom lens system of Example 10 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located neater to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which is integrally provided with an aperture stop on its image side, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the image side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a concave reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and reaches the telephoto end where it is located somewhat neater to the image side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the zoom lens system. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 8.1246 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 2.3175 mm.

[0159] In Example 10, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a double-concave lens with an image-side surface thereof provided with a thin resin layer thereby making that surface aspheric, a double-concave lens, a negative meniscus lens convex on its image side and two double-convex lenses, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the image-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0160] As shown in FIG. 11, the zoom lens system of Example 11 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which is integrally provided with an aperture stop on its image side, remains fixed, the fourth lens group G4 moves toward the object side of the system, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then slightly wide and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the zoom lens system. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 6.6911 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 3.0700 mm.

[0161] In Example 11, the first lens group G1 is made up of two lenses, i.e., a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, two double-concave lenses and a double-convex lens, the third lens group G3 is made up of a negative meniscus lens convex on its object side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the image-side surface of the double-convex lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0162] As shown in FIG. 12, the zoom lens system of Example 12 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the system than at the location of the wide-angle end, the second lens group G2 moves to the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then slightly wide, and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the system. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 6.0167 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 2.1156 mm.

[0163] In Example 12, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, two double-concave lenses and a double-convex lens, the third lens group G3 is made up of a double-concave lens and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its object side. Three aspheric surfaces are used, one for the object-side surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0164] As shown in FIG. 13, the zoom lens system of Example 13 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having positive refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its object side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.3354 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 1.7386 mm.

[0165] In Example 13, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a double-concave lens with an object-side surface thereof provided with a thin resin layer thereby making that surface aspheric and a double-convex lens, the third lens group G3 is made up of a stop and a double-convex lens, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a positive meniscus lens convex on its image side and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0166] As shown in FIG. 14, the zoom lens system of Example 14 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power, a fourth lens group G4 having negative refracting power and a fifth lens group G5 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a concave reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, and the fifth lens group G5 moves toward the object side while the spacing between the fourth lens group G4 and the fifth lens group G5 becomes narrow. For focusing on a nearby subject, the fifth lens group G5 is designed to move out toward the object side of the zoom lens system. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 7.5416 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 0.5503 mm.

[0167] In Example 14, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a doublet consisting of a double-concave lens and a negative meniscus lens convex on its object side and a double- convex lens, the third lens group G3, with the fixed stop located between the second lens group G2 and the third lens group G3, is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fourth lens group G4 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the fifth lens group G5 is made up of a double-convex lens and a positive meniscus lens convex on its image side. Three aspheric surfaces are used, one for the object-side surface of the doublet in the second lens group G2, one for the object-side surface of the double-convex lens in the third lens group G3 and one for the object-side surface of the double-convex lens in the fifth lens group G5.

[0168] As shown in FIG. 15, the zoom lens system of Example 15 is made up of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power, a fourth lens group G4 having negative refracting power and a fifth lens group G5 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, and the fifth lens group G5 moves toward the object side while the spacing between the fourth lens group G4 and the fifth lens group G5 becomes narrow. For focusing on a nearby subject, the fifth lens group G5 is designed to move out toward the object side of the zoom lens system. More specifically, when the zoom lens system is focused on a nearby subject on the wide-angle end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 7.8923 mm, and when focused on a nearby subject on the telephoto end, the spacing between the fourth lens group G4 and the fifth lens group G5 is set at 2.3128 mm.

[0169] In Example 15, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a double-concave lens with an object-side surface thereof provided with a thin resin layer thereby making that surface aspheric and a double-convex lens, the third lens group G3, with the fixed stop located between the second lens group G2 and the third lens group G3, is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fourth lens group G4 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the fifth lens group G5 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, the object-side surface of the double-convex lens in the third lens group G3 and one for the object-side surface of the double-convex lens in the fifth lens group G5.

[0170] As shown in FIG. 16, the zoom lens system of Example 16 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the fifth lens group G5 and the sixth lens group G6 becomes narrow and then slightly wide and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the system. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.6961 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 3.0968 mm.

[0171] In Example 16, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens, a double-convex lens and a negative meniscus lens convex on its image side, the third lens group G3 is made up of a double-concave lens and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0172] As shown in FIG. 17, the zoom lens system of Example 17 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then slightly wide, and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the zoom lens system. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 6.0079 mm, and when focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 2.6039 mm.

[0173] In Example 17, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, two double-concave lenses and a double-convex lens, the third lens group G3 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are used, one for the object-side surface of the second double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0174] As shown in FIG. 18, the zoom lens system of Example 18 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a fourth lens group G6. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side than at the location of the wide-angle end, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and then slightly wide and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby object, the sixth lens group G6 is designed to move toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 6.0177 mm, and when focused on a nearby subject, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 2.2983 mm.

[0175] In Example 18, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, two double-concave lenses and a double-convex lens, the third lens group G3 is made up of a plano-concave lens and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Four aspheric surfaces are used, one for the object-side surface of the second double-concave lens in the second lens group G2, one for the image-side surface of the plano-concave lens in the third lens group G3, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0176] As shown in FIG. 19, the zoom lens system of Example 19 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power and a fourth lens group G4 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, and the fourth lens group G4 moves toward the object side while the spacing between the third lens group G3 and the fourth lens group G4 becomes wide. For focusing on a nearby subject, the fourth lens group G4 is designed to move out toward the object side of the system.

[0177] In Example 19, the first lens group G1 is made up of a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens and a positive meniscus lens convex on its object side, and the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens and two double-convex lenses. The fixed stop is located between the second lens group G2 and the third lens group G3. The third lens group G3 is made up of a double-convex lens and a doublet consisting of a positive meniscus lens convex on its object side and a negative meniscus lens convex on its object side, and the fourth lens group G4 is made up of a positive meniscus lens convex on its object side and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens. Three aspheric surfaces are provided, one for the image-side surface of the double-concave lens in the second lens group G2, one for the object-side surface of the double-convex lens in the third lens group G3 and one for the surface located nearest to the image side in the fourth lens group G4.

[0178] As shown in FIG. 20, the zoom lens system of Example 20 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a fixed aperture stop, a third lens group G3 having positive refracting power, a fourth lens group G4 having negative refracting power and a fifth lens group G5. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side while the spacing between the third lens group G3 and the fourth lens group G4 becomes wide, and the fifth lens group G5 moves toward the object side while the spacing between the fourth lens group G4 and the fifth lens group G5 becomes narrow and then slightly wide. For focusing on a nearby subject, the fifth lens group G5 is designed to move out toward the object side.

[0179] In Example 20, the first lens group G1 is made up of a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens and a positive meniscus lens convex on its object side, and the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens. The fixed stop is located between the second lens group G2 and the third lens group G3. The third lens group G3 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a double-concave lens, the fourth lens group G4 is made up of a doublet consisting of a positive meniscus lens convex on its image side and a double-concave lens, and the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a double-convex lens and a double-convex lens. Three aspheric surfaces are provided, one for the image-side surface of the negative meniscus lens in the second lens group G2, one for the surface of the doublet in the third lens group G3, which is located nearest to the object side, and one for the surface of the doublet in the fifth lens group G5, which is located nearest to the image side.

[0180] As shown in FIG. 21, the zoom lens system of Example 21 is composed of a first lens group G1 having positive refracting power, a second lens group C2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G5 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the image side than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its object side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the object side while the spacing between the spacing between the fourth lens group G4 and the fifth lens group G5 becomes wide, and the sixth lens group G6 moves toward the object side while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes slightly wide and then slightly narrow. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side.

[0181] In Example 21, the first lens group G1 is made up of a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the second lens group G2 is made up of a negative meniscus lens convex on its object side, two double-concave lenses and a double-convex lens, the third lens group G3 is made up of a stop and a negative meniscus lens convex on its image side, the fourth lens group G4 is made up of a positive meniscus lens convex on its object side and a doublet consisting of a double-convex lens and a double-concave lens, the fifth lens group G5 is made up of a doublet consisting of a positive meniscus lens convex on its object side and a negative meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its image side and a double-convex lens. Three aspheric surfaces are provided, one for the image-side surface of the negative meniscus lens in the second lens group G2, one for the surface of the doublet in the fourth lens group G4, which is located nearest to the image side, and one for the image-side surface of the double-convex lens in the sixth lens group G6.

[0182] As shown in FIG. 22, the zoom lens system of Example 22 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the image side, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the zoom lens system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 10.6679 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 1.0776 mm.

[0183] In Example 22, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens with an image-side surface thereof provided with a thin resin layer thereby making that surface aspheric and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side resin layer surface of the double-concave lens in the second lens group G2, the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0184] As shown in FIG. 23, the zoom lens system of Example 23 is composed of a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the system than at the location of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the image side, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and reaches the telephoto end where it is located somewhat nearer to the object side than at the location of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 9.3998 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 0.9516 mm.

[0185] In Example 23, the first lens group G1 is made up of a negative meniscus lens convex on its object side and two positive meniscus lenses, each convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a negative meniscus lens convex on its image side and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the object-side surface of the negative meniscus lens in the second lens group G2, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0186] As shown in FIG. 24, the zoom lens system of Example 24 is composed of a first lens group having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the system than at the position of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the image side, and the sixth lens group G6 moves toward the object side in a convex reciprocation locus while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and reaches the telephoto end where it is located somewhat nearer to the object side than at the position of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side of the system. More specifically, when the system is focused on a nearby subject at the wide angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 9.73471 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 0.8531 mm.

[0187] In Example 24, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a negative meniscus lens convex on its image side and a doublet consisting of a negative meniscus lens convex on its image side and a positive meniscus lens convex on its image side, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the image-side surface of the negative meniscus lens in the second lens group G2, which lens is convex on its image side, one for the object-side surface of the double-convex lens in the fourth lens group G4, and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0188] As shown in FIG. 25, the zoom lens system of Example 25 is composed of a first lens group G1 having positive refracting power, a second lens group C2 having negative refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power, a fifth lens group G5 having negative refracting power and a sixth lens group G6 having positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens system when focused on an object point at infinity, the first lens group G1 moves toward the image side of the zoom lens system in a convex reciprocation locus and reaches the telephoto end where it is located nearer to the object side of the zoom lens system than at the position of the wide-angle end, the second lens group G2 moves toward the image side, the third lens group G3, which has an aperture stop on its image side as an integral piece, remains fixed, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves toward the image side, and the sixth lens group G6 moves toward the object side while the spacing between the fifth lens group G5 and the sixth lens group G6 becomes narrow and reaches the telephoto end where it is located somewhat nearer to the image side than at the position of the wide-angle end. For focusing on a nearby subject, the sixth lens group G6 is designed to move out toward the object side. More specifically, when the system is focused on a nearby subject at the wide-angle end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 7.9914 mm, and when focused on a nearby subject at the telephoto end, the spacing between the fifth lens group G5 and the sixth lens group G6 is set at 1.4726 mm.

[0189] In Example 25, the first lens group G1 is made up of a negative meniscus lens convex on its object side, a double-convex lens and a positive meniscus lens convex on its object side, the second lens group G2 is made up of a negative meniscus lens convex on its object side, a double-concave lens and a doublet consisting of a double-concave lens and a double-convex lens, the third lens group G3 is made up of a negative meniscus lens convex on its image side and a stop, the fourth lens group G4 is made up of a double-convex lens and a doublet consisting of a negative meniscus lens convex on its object side and a double-convex lens, the fifth lens group G5 is made up of a doublet consisting of a double-concave lens and a positive meniscus lens convex on its object side, and the sixth lens group G6 is made up of a double-convex lens and a doublet consisting of a double-convex lens and a negative meniscus lens convex on its image side. Three aspheric surfaces are provided, one for the surface of the doublet in the second lens group G2, which is located nearest to the image side, one for the object-side surface of the double-convex lens in the fourth lens group G4 and one for the object-side surface of the double-convex lens in the sixth lens group G6.

[0190] Throughout Examples 1 to 25, it is acceptable to make the amount of focusing movement larger than exemplified above, thereby focusing the system on a more nearby subject.

[0191] Enumerated below are the data on each example. However, it is noted that the symbols used hereinafter but not hereinbefore have the following meanings.

[0192] f is the focal length of the zoom lens system, ω is the half field angle of the system, F_(NO) is the F-number of the system, W is the wide-angle end of the system, WS is an intermediate state between the wide-angle end and a standard state (the geometric means of the wide-angle end and the standard state), S is the standard state, ST is an intermediate state between the standard state and the telephoto end of the system, T is the telephoto end of the system, r₁, r₂ . . . are the radii of curvature of the respective lens surfaces, d₁, d₂ . . . are the spacing between adjacent lens surfaces, n_(d1), n_(d2) . . . are the d-line refractive indices of the respective lenses, and ν_(d1), ν_(d2) . . . are the Abbe constants of the respective lenses. Here let x stand for an optical axis where the direction of propagation of light is positive and y represent a direction perpendicular to the optical axis. Then, aspheric surface shape is given by

x=(y ² /r)/[1+{1−(K+1) (y/r)²}^(½) ]+A ₄ y ⁴ +A ₆ y ⁶ +A ₈ y ⁸ +A ₁₀ y ¹⁰

[0193] where r is a paraxial radius of curvature, K is a conical coefficient, and A₄, A₆, A₈ and A₁₀ are the fourth, sixth, eighth and tenth aspherical coefficients. Example 1  r₁ = 144.6796  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 82.7855  d₂ = 0.2000  r₃ = 86.4734  d₃ = 6.6250  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = −587.8788  d₄ = 0.2000  r₅ = 67.2317  d₅ = 4.9655  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 245.5595  d₆ = (Variable)  r₇ = −2.080 × 10⁴  d₇ = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 17.9014  d₈ = 8.5657  r₉ = 66.4539  d₉ = 0.2000  n_(d5) = 1.53508  ν_(d5) = 40.94 (Aspheric) r₁₀ = −145.6382 d₁₀ = 1.3000  n_(d6) = 1.77250  ν_(d6) = 49.60 r₁₁ = 275.5575 d₁₁ = 4.1902 r₁₂ = −23.6269 d₁₂ = 1.1790  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = −120.2094 d₁₃ = 4.4826  n_(d8) = 1.84666  ν_(d8) = 23.78 r₁₄ = −36.0216 d₁₄ = (Variable) r₁₅ = −13.3441 d₁₅ = 1.3000  n_(d9) = 1.77250  ν_(d9) = 49.60 r₁₆ = 14.7782 d₁₆ = 1.0476 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 22.2411 d₁₈ = 5.1519 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₁₉ = −44.3261 d₁₉ = 0.1026 r₂₀ = 66.0894 d₂₀ = 1.1010 n_(d11) = .80610 ν_(d11) = 40.92 r₂₁ = 17.8460 d₂₁ = 5.1279 n_(d12) = 449700 ν_(d12) = 81.54 r₂₂ = 87.9421 d₂₂ = (Variable) r₂₃ = −55.9458 d₂₃ = 0.9000 n_(d13) = 45l633 ν_(d13) = 64.14 r₂₄ = 13.4125 d₂₄ = 3.2354 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₅ = 19.3681 d₂₅ = (Variable) r₂₆ = 26.8826 d₂₆ = 4.2125 n_(d15) = 1.49700 ν_(d15) = 81.54 (Aspheric) r₂₇ = −27.8744 d₂₇ = 0.1500 r₂₈ = 279.7814 d₂₈ = 4.1538 nd₁₆ = 1.61800 ν_(d16) = 63.33 r₂₉ = −15.8089 d₂₉ = 1.0000 nd₁₇ = 1.84666 ν_(d17) = 23.78 r₃₀ = 57.4983 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 nd₁₈ = 4.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 nd₁₉ = 4.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₆ = ∞ d₃₅ = 0.7500 nd₂₀ = 1.51633 ν_(d20) = 64.14 r₃₇ = ∞ d₃₆ = 1.2400 Aspherical Coefficients 9th surface  K = 0  A₄ = 2.1263 × 10⁻⁵  A₆ = 1.5727 × 10⁻⁸  A₈ = 3.9610 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −1.9875 × 10⁻⁵  A₆ = −1.3029 × 10⁻⁸  A₈ = 5.1888 × 10⁻¹¹ A₁₀ = 0.0000 26th surface  K = 0  A₄ = −1.7061 × 10⁻⁵  A₆ = −8,7539 × 10⁻⁹  A₈ = 1.1345 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26000 12.99999 23.29997 41.72984 74.74939 F_(NO) 2.8000 3.3795 3.5000 3.5000 3.5000 ω (°) 38.45 . 13.04 . 4.12 d₆ 1.68869 10.56701 29.85764 47.13961 57.82811 d₁₄ 44.76569 23.28314 12.25974 6.30842 2.57394 d₁₇ 19.00232 11.35026 8.66100 6.27017 0.99971 d₂₂ 1.50000 7.83915 11.97947 16.04050 22.86634 d₂₅ 8.26323 8.96815 6.46694 5.08222 5.08574 d₃₀ 4.69246 5.30046 6.35060 6.06512 4.50622 Example 2  r₁ = 82.4483  d₁ = 2.6000  n_(d1) = 4.846661  ν_(d1) = 23.78  r₂ = 57.4502  d₂ = 0.1000  r₃ = 57.9164  d₃ = 7.1329  n_(d2) = 4.497002  ν_(d2) = 81.54  r₄ = 284.4315  d₄ = 0.2000  r₅ = 69.2991  d₅ = 5.3163  n_(d3) = 4.603112  ν_(d3) = 60.64  r₆ = 400.4019  d₆ = (Variable)  r₇ = 1559.7350  d₇ = 1.5000  n_(d4) = 4.772502  ν_(d4) = 49.60  r₈ = 18.3563  d₈ = 8.8487  r₉ = −51.0656  d₉ = 1.3643  n_(d5) = 4.77250  ν_(d5) = 49.60 r₁₀ = 89.9326 d₁₀ = 0.2000  n_(d6) = 4.53508  ν_(d6) = 40.94 r₁₁ = 56.6440 d₁₁ = 2.9409 (Aspheric) r₁₂ = −70.2481 d₁₂ = 1.1135  n_(d7) = 4.48749  ν_(d7) = 70.23 r₁₃ = −351.6349 d₁₃ = 3.8722  n_(d8) = 4.84666  ν_(d8) = 23.78 r₁₄ = −41.4750 d₁₄ = (Variable) r₁₅ = −21.7766 d₁₅ = 1.0673  n_(d9) = 4.69680  ν_(d9) = 55.53 r₁₆ = −24.1145 d₁₆ = 1.4225 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 21.1358 d₁₈ = 5.4704 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₁₉ = −79.1895 d₁₉ = 0.1774 r₂₀ = 47.1634 d₂₀ = 1.1410 n_(d11) = 1.80440 ν_(d11) = 39.59 r₂₁ = 15.0512 d₂₁ = 3.4835 n_(d12) = 4.61800 ν_(d12) = 63.33 r₂₂ = −184.9380 d₂₂ = (Variable) r₂₃ = 74.7571 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 11.7718 d₂₄ = 1.9155 n_(d14) = 4.84666 ν_(d14) = 23.78 r₂₅ = 17.1123 d₂₅ = (Variable) r₂₆ = 37.8693 d₂₆ = 3.4588 n_(d15) = 1.497002 ν_(d15) = 81.54 (Aspheric) r₂₇ = −21.7737 d₂₇ = 0.1500 r₂₈ = −131.6293 d₂₈ = 3.7575 n_(d16) = 1.61800 ν_(d16) = 63.33 r₂₉ = −12.5491 d₂₉ = 1.0000 n_(d17) = 4.84666 ν_(d17) = 23.78 r₃₀ = 38.2936 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d18) = 1.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = −2.3956 × 10⁻⁵  A₆ = 1.1363 × 10⁻⁸  A₈ = −2.9304 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −1.9310 × 10⁻⁵  A₆ = −5.6603 × 10⁻⁹  A₈ = −5.6829 × 10⁻¹¹ A₁₀ = 0.0000 26th surface  K = 0  A₄ = −1.9084 × 10⁻⁵  A₆ = 8.1108 × 10⁻⁹  A₈ = 2.2527 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.2599 12.99998 23.29994 41.72977 74.74923 F_(NO) 2.8000 3.0773 3.4040 3.5000 3.5000 ω (°) 38.47 . 13.05 . 4.09 d₆ 2.04129 12.03456 30.35700 47.31707 58.11117 d₁₄ 52.08359 23.80135 12.15120 5.17137 2.10989 d₁₆ 15.96754 11.83766 8.87742 6.74717 1.12789 d₂₂ 1.50000 4.35576 7.49811 10.64193 17.10388 d₂₅ 7.96197 7.07284 5.58079 4.44519 5.93947 d₃₀ 4.69339 6.85663 8.16658 8.28861 5.95167 Example 3  r₁ = 79.8928  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 56.5419  d₂ = 0.0932  r₃ = 56.8568  d₃ = 7.2921  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 279.2946  d₄ = 0.2000  r₅ = 71.4740  d₅ = 5.1087  n_(d3) = 1.603112  ν_(d3) = 60.64  r₆ = 368.5676  d₆ = (Variable)  r₇ = 297.1098  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 16.7226  d₈ = 8.2214  r₉ = −58.5814  d₉ = 1.3643  n_(d5) = 1.772502  ν_(d5) = 49.60 r₁₀ = 42.9833 d₁₀ = 2.8172 r₁₁ = 44.9540 d₁₁ = 2.4853  n_(d6) = 1.688932  ν_(d6) = 31.07 r₁₂ = 67.5910 d₁₂ = 0.5000  n_(d7) = 1.53508  ν_(d7) = 10.94 r₁₃ = 60.4446 d₁₃ = 2.4132 (Aspheric) r₁₄ = −152.6589 d₁₄ = 2.7489  n_(d8) = 1.846662  ν_(d8) = 23.78 r₁₅ = −43.1824 d₁₅ = (Variable) r₁₆ = 1521.7545 d₁₆ = 1.2383  n_(d9) = 1.696802  ν_(d9) = 55.53 r₁₇ = 103.2631 d₁₇ = 1.3581 r₁₈ = ∞ (Stop) d₁₈ = (Variable) r₁₉ = 19.8319 d₁₉ = 6.0797 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₂₀ = −98.1431 d₂₀ = 0.1774 r₂₁ = 41.2385 d₂₁ = 1.1410 n_(d11) = 1.80440 ν_(d11) = 39.59 r₂₂ = 13.6120 d₂₂ = 5.6638 n_(d12) = 1.60311 ν_(d12) = 60.64 r₂₃ = −105.3016 d₂₃ = (Variable) r₂₄ = −60.3378 d₂₄ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₅ = 11.2684 d₂₅ = 2.0556 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₆ = 16.0592 d₂₆ = (Variable) r₂₇ = 57.5023 d₂₇ = 3.0046 n_(d15) = 1.497002 ν_(d15) = 81.54 r₂₈ = −29.3958 d₂₈ = 0.1500 (Aspheric) r₂₉ = 60.6802 d₂₉ = 4.8459 n_(d16) = 1.60311 ν_(d16) = 60.64 r₃₀ = −12.9748 d₃₀ = 1.0000 n_(d17) = 484666 ν_(d17) = 23.78 r₃₁ = 47.6191 d₃₁ = (Variable) r₃₂ = ∞ d₃₂ = 16.0000 n_(d18) = −1.51633 ν_(d18) = 64.14 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₅ = ∞ d₃₅ = 1.0000 r₃₆ = ∞ d₃₆ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₇ = ∞ d₃₇ = 1.2400 r₃₈ = ∞ Aspherical Coefficients 13th surface  K = 0  A₄ = −1.4437 × 10⁻⁵  A₆ = 2.9795 × 10⁻⁹  A₈ = −9.7997 × 10⁻¹² A₁₀ = 0.0000 19th surface  K = 0  A₄ = −1.9829 × 10⁻⁵  A₆ = −1.2490 × 10⁻⁸  A₈ = 9.5912 × 10⁻¹² A₁₀ = 0.0000 28th surface  K = 0  A₄ = −8.0968 × 10⁻⁶  A₆ = −1.4115 × 10⁻⁸  A₈ = −3.7788 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26002 13.00003 23.30008 41.73033 74.75116 F_(NO) 2.8003 3.0838 3.4742 3.5003 3.5007 ω (°) 38.42 . 13.05 . 4.11 d₆ 1.36006 12.49834 30.21824 47.74332 58.25431 d₁₅ 54.96399 24.89992 12.03611 4.74729 1.70314 d₁₈ 17.14336 12.83290 9.24821 6.81249 1.02608 d₂₃ 1.50000 3.50570 6.35732 8.92130 16.08346 d₂₆ 7.83356 7.52870 6.60733 5.98190 6.80232 d₃₁ 5.02576 7.63538 9.28981 9.78699 7.59082 Example 4  r₁ = 81.6544  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 54.5219  d₂ = 0.0918  r₃ = 55.1373  d₃ = 6.6789  n_(d2) = 1.60311  ν_(d2) = 60.64  r₄ = 170.0871  d₄ = 0.2000  r₅ = 63.9518  d₅ = 5.5295  n_(d3) = 1.603112  ν_(d3) = 60.64  r₆ = 261.7938  d₆ = (Variable)  r₇ = 135.9397  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 18.6691  d₈ = 7.1069  r₉ = −77.9436  d₉ = 1.3643  n_(d5) = 1.772502  ν_(d5) = 49.60 r₁₀ = 29.3916 d₁₀ = 3.6128 r₁₁ = −136.6311 d₁₁ = 2.6052  n_(d6) = 1.68893  ν_(d6) = 31.07 (Aspheric) r₁₂ = −93.2719 d₁₂ = 1.2000  n_(d7) = 1.772502  ν_(d7) = 49.60 r₁₃ = 48.4132 d₁₃ = 0.1500 r₁₄ = −40.2538 d₁₄ = 5.6753  n_(d8) = 1.688932  ν_(d8) = 31.07 r₁₅ = 41.2699 d₁₅ = (Variable) r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 20.5800 d₁₇ = 3.1262  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −89.3640 d₁₈ = 0.1500 r₁₉ = 221.1623 d₁₉ = 3.2743 n_(d10) = 1.48749 ν_(d10) = 70.23 r₂₀ = −22.6962 d₂₀ = 1.0743 n_(d11) = 1.69895 ν_(d11) = 30.13 r₂₁ = −65.3546 d₂₁ = (Variable) r₂₂ = −44.1685 d₂₂ = 2.2362 n_(d12) = 1.846662 ν_(d12) = 23.78 r₂₃ = −17.9114 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 19.1017 d₂₄ = (Variable) r₂₅ = 26.6661 d₂₅ = 3.6847 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −34.1574 d₂₆ = 0.1500 r₂₇ = −52.2108 d₂₇ = 4.2853 n_(d15) = −1.49700 ν_(d15) = 81.54 r₂₈ = −14.7656 d₂₈ = 1.2000 n_(d16) = 1.80518 ν_(d16) = 25.42 r₂₉ = −55.0799 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₅ = 1.2400 r₃₆ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 1.0139 × 10⁻⁵  A₆ = 3.2872 × 10⁻⁹  A₈ = −1.1023 × 10⁻¹¹ A₁₀ = = 0.0000 17th surface  K = 0  A₄ = −1.7036 × 10⁻⁵  A₆ = −1.7437 × 10⁻⁸  A₈ = 4.5946 × 10⁻¹¹ A₁₀ = 0.0000 25th surface  K = 0  A₄ = 3.4248 × 10⁻⁶  A₆ = 1.4711 × 10⁻⁸  A₈ = 4.5298× 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.25999 . 23.29992 . 74.74889 F_(NO) 2.8000 . 3.5801 . 3.5000 ω (°) 38.54 . 13.22 . 4.14 d₆ 1.00000 14.89793 31.05521 47.12742 59.32091 d₁₅ 52.30556 29.13766 15.90712 7.48462 2.50000 d₁₆ 20.23714 12.06038 7.38350 5.16625 1.27216 d₂₁ 3.72767 5.35270 8.32036 10.89531 15.89787 d₂₄ 3.24286 7.15116 6.72019 5.06310 5.57919 d₂₆ 4.69211 7.33554 9.47573 10.77513 9.15056 Example 5  r₁ = 78.1210  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 52.5351  d₂ = 0.0776  r₃ = 53.2073  d₃ = 6.8025  n_(d2) = 1.60311  ν_(d2) = 60.64  r₄ = 159.3705  d₄ = 0.2000  r₅ = 65.8776  d₅ = 5.5331  n_(d3) = 1.60311  ν_(d3) = 60.64  r₆ = 303.8063  d₆ = (Variable)  r₇ = 163.0022  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 19.60  r₈ = 17.9806  d₈ = 6.9388  r₉ = −95.4021  d₉ = 1.3643  n_(d5) = 1.77250  ν_(d5) = 49.60 r₁₀ = 31.9739 d₁₀ = 3.3248 r₁₁ = −83.4161 d₁₁ = 2.2162  n_(d6) = 1.68893  ν_(d6) = 31.07 (Aspheric) r₁₂ = −51.8821 d₁₂ = 1.2000  n_(d7) = 1.77250  ν_(d7) = 49.60 r₁₃ = 110.2656 d₁₃ = 0.1500 r₁₄ = 52.7805 d₁₄ = 4.8751  n_(d8) = 1.68893  ν_(d8) = 31.07 r₁₅ = −44.3555 d₁₅ = (Variable) r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 20.3453 d₁₇ = 4.8644  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −18.1397 d₁₈ = 0.1995 r₁₉ = −17.0247 d₁₉ = 0.9865 n_(d10) = 1.58144 ν_(d10) = 10.75 r₂₀ = −41.9737 d₂₀ = (Variable) r₂₁ = −34.7870 d₂₁ = 1.6000 n_(d11) = 1.84666 ν_(d11) = 23.78 r₂₂ = −15.2340 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = 20.7010 d₂₃ = (Variable) r₂₄ = 21.6523 d₂₄ = 1.2000 n_(d13) = 1.80518 ν_(d13) = 25.42 r₂₅ = 11.8448 d₂₅ = 5.1050 n_(d14) = 1.49700 ν_(d14) = 81.54 r₂₆ = 282.0413 d₂₆ = 0.1500 r₂₇ = 18.6629 d₂₇ = 5.4207 n_(d15) = 1.49700 ν_(d15) = 81.54 r₂₈ = −35.6003 d₂₈ = 0.1500 (Aspheric) r₂₉ = 45.1746 d₂₉ = 1.0526 n_(d16) = 1.80518 ν_(d16) = 25.42 r₃₀ = 26.6635 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₂ = ∞ d₃₂ = ∞1.0000 r₃₃ = ∞ d₃₃ = ∞2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₄ = ∞ d₃₄ = ∞1.0000 r₃₅ = ∞ d₃₅ = ∞0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₆ = ∞ d₃₆ = ∞1.2400 r₃₇ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 7.1125 × 10⁻⁶  A₆ = 2.0512 × 10⁻⁸  A₈ = −5.1595 × 10⁻¹¹ A₁₀ = 0.0000 17th surface  K = 0  A₄ = −1.5184 × 10⁻⁵  A₆ = −2.3566 × 10⁻⁸  A₈ = 3.4360 × 10⁻¹⁰ A₁₀ = 0.0000 28th surface  K = 0  A₄ = 3.1780 × 10⁻⁵  A₆ = −9.9597 × 10⁻⁸  A₈ = −5.2192 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.25999 . 23.29997 . 74.75182 F_(NO) 2.8000 . 3.5778 . 3.5000 ω (°) 38.52 . 13.19 . 4.13 d₆ 1.04546 15.02846 31.09889 46.16763 59.30495 d₁₅ 52.08237 29.21796 16.44547 7.46848 2.50000 d₁₆ 19.83770 12.09302 7.11800 4.38285 1.23876 d₂₀ 2.85510 5.90624 9.13593 11.32215 15.45881 d₂₃ 4.36441 7.15116 6.72019 5.06310 5.57919 d₃₀ 5.49442 7.40121 9.57751 11.78353 10.27488 Example 6  r₁ = 141.6786  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 82.2770  d₂ = 0.2054  r₃ = 86.0098  d₃ = 6.6214  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = −623.7275  d₄ = 0.2000  r₅ = 66.9330  d₅ = 4.9709  n_(d3) = 1.69680  ν_(d3) = 5.53  r₆ = 242.1492  d₆ = (Variable)  r₇ = −1681.4393  d₇ = 1.7000  n_(d4) = 177250  ν_(d4) = 49.60  r₈ = 17.8527  d₈ = 8.5980  r₉ = −59.5314  d₉ = 0.2000  n_(d5) = 1.53508  ν_(d5) = 10.94 (Aspheric) r₁₀ = −119.6362 d₁₀ = 1.3000  n_(d6) = 1.77250  ν_(d6) = 19.60 r₁₁ = 342.3608 d₁₁ = 4.1895 r₁₂ = −24.2842 d₁₂ = 1.1790  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = −101.8680 d₁₃ = 4.5574  n_(d8) = 1.84666  ν_(d8) = 23.78 r₁₄ = −33.5232 d₁₄ = (Variable) r₁₅ = −17.5269 d₁₅ = 1.3000  n_(d9) = 1.77250  ν_(d9) = 19.60 r₁₆ = −20.0488 d₁₆ = 1.0127 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 21.3027 d₁₈ = 5.1829 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₁₉ = −71.1108 d₁₉ = 0.0740 r₂₀ = 64.9416 d₂₀ = 1.1010 n_(d11) = 1.80610 ν_(d11) = 40.92 r₂₁ = 16.9316 d₂₁ = 5.1171 n_(d12) = 1.49700 ν_(d12) = 81.54 r₂₂ = −53.3840 d₂₂ = (Variable) r₂₃ = −52.6066 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 13.9038 d₂₄ = 3.2142 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₅ = 21.1652 d₂₅ = (Variable) r₂₆ = 30.4474 d₂₆ = 5.0612 n_(d15) = 1.49700 ν_(d15) = 81.54 (Aspheric) r₂₇ = −27.3044 d₂₇ = 0.1500 r₂₈ = 172.6100 d₂₈ = 4.5076 n_(d16) = 1.61800 ν_(d16) = 63.33 r₂₉ = −16.2580 d₂₉ = 1.0000 n_(d17) = 1.84666 ν_(d17) = 23.78 r₃₀ = −61.9158 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d18) = 4.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 2.2129 × 10⁻⁵  A₆ = 6.5725 × 10⁻¹⁰  A₈ = 7.2804 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −1.8979 × 10⁻⁶  A₆ = 8.7960 × 10⁻⁹  A₈ = −1.5301 × 10⁻¹⁰ A₁₀ = 0.0000 26th surface  K = 0  A₄ = −1.7277 × 10⁻⁵  A₆ = 3.9898× 10⁻⁹  A₈ = −5.5382 × 10⁻¹¹ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26002 13.00003 23.30013 41.73069 74.75304 F_(NO) 2.8000 3.4061 3.5000 3.5000 3.5000 ω (°) 38.45 . 13.03 . 4.12 d₆ 1.69990 10.56611 29.95684 47.14010 57.75352 d₁₄ 38.83846 18.70163 9.09372 4.72000 2.59257 d₁₇ 25.00055 15.77754 11.57455 7.61504 1.02237 d₂₂ 1.49193 7.85215 11.95770 16.03342 23.12571 d₂₅ 8.12406 8.99710 6.58794 5.19826 5.37687 d₃₀ 4.61121 5.36097 6.51641 6.38966 4.90755 Example 7  r₁ = 133.2906  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 2378  r₂ = 79.7190  d₂ = 0.4683  r₃ = 88.0849  d₃ = 6.7955  n_(d2) = 1.497002  ν_(d2) = 81.54  r₄ = −928.2450  d₄ = 0.2000  r₅ = 61.1424  d₅ = 5.7149  n_(d3) = 1.603112  ν_(d3) = 60.64  r₆ = 290.9980  d₆ = (Variable)  r₇ = 858.6153  d₇ = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 17.2556  d₈ = 8.7043  r₉ = −65.5194  d₉ = 0.2000  n_(d5) = −1.53508  ν_(d5) = 40.94 (Aspheric) r₁₀ = −103.0065 d₁₀ = 1.3000  n_(d6) = 4.77250  ν_(d6) = 49.60 r₁₁ = 207.4789 d₁₁ = 3.9972 r₁₂ = −29.5057 d₁₂ = 1.2706  n_(d7) = 4.60311  ν_(d7) = 60.64 r₁₃ = −3.472× 104 d₁₃ = 4.4191  n_(d8) = 4.84666  ν_(d8) = 23.78 r₁₄ = −39.4285 d₁₄ = (Variable) r₁₅ = −14.2222 d₁₅ = 1.3000  n_(d9) = 1.77250  ν_(d9) = 49.60 r₁₆ = −15.6911 d₁₆ = 0.9994 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 29.1466 d₁₈ = 5.3713 n_(d10) = 1.49700 ν_(d1081.54) (Aspheric) r₁₉ = −55.2100 d₁₉ = 0.1000 r₂₀ = −2878.6841 d₂₀ = 1.0357 n_(d11) = 1.69895 ν_(d11) = 30.13 r₂₁ = 26.7931 d₂₁ = 5.3045 n_(d12) = 1.61800 ν_(d12) = 63.33 r₂₂ = 52.9610 d₂₂ = (Variable) r₂₃ = −72.6679 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 14.0385 d₂₄ = 3.1899 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₅ = 23.1764 d₂₅ = (Variable) r₂₆ = 34.1187 d₂₆ = 4.0924 n_(d15) = 1.49700 ν_(d15) = 81.54 (Aspheric) r₂₇ = −27.1159 d₂₇ = 0.1500 r₂₈ = −179.2221 d₂₈ = 4.5403 n_(d16) = 1.61800 ν_(d16) = 63.33 r₂₉ = −13.8901 d₂₉ = 1.0000 n_(d17) = 1.84666 ν_(d17) = 23.78 r₃₀ = −48.2993 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d18) = 1.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 2.2685 × 10⁻⁶  A₆ = −9.9328 × 10⁻⁹  A₆ = 6.5515 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −1.5955 × 10⁻⁵  A₆ = 1.0315 × 10⁻⁸  A₈ = −9.0638 × 10⁻¹¹ A₁₀ = 0.0000 26th surface  K = 0  A₄ = −1.7668 × 10⁻⁵  A₆ = −1.6378 × 10⁻⁹  A₈ = 5.8919 × 10⁻¹¹ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.25994 12.99979 23.29960 41.72935 74.74958 F_(NO) 2.8000 3.2736 3.5000 3.5000 3.5000 ω (°) 38.48 . 13.03 . 4.10 d₆ 1.57613 10.58693 29.66082 47.22031 57.38048 d₁₄ 35.33624 14.67575 7.05728 3.95447 2.57253 d₁₇ 27.90225 18.46229 13.50552 9.05177 1.02205 d₂₂ 2.01227 6.50604 11.64080 16.22329 23.37367 d₂₅ 7.59111 7.59111 7.59111 7.59111 7.59111 d₃₀ 4.35060 6.30937 6.83154 6.23847 5.63660 Example 8  r₁ = 154.0084  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 85.1308  d₂ = 0.2000  r₃ = 89.0506  d₃ = 6.8812  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = −500.6640  d₄ = 0.2000  r₅ = 71.0865  d₅ = 4.9871  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 321.2628  d₆ = (Variable)  r₇ = −1661.3349  d₇ = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 18.0950  d₈ = 8.8337  r₉ = −62.2296  d₉ = 0.2000  n_(d5) = 1.53508  ν_(d5) = 40.94 (Aspheric) r₁₀ = −129.5877 d₁₀ = 1.3000  n_(d6) = 1.77250  ν_(d6) = 49.60 r₁₁ = 1178.5652 d₁₁ = 3.1344 r₁₂ = −33.4282 d₁₂ = 1.1790  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = 90.9167 d₁₃ = 4.3569  n_(d8) = 1.84666  ν_(d8) = 23.78 r₁₄ = 65.5020 d₁₄ = (Variable) r₁₅ = ∞(Stop) d₁₅ = 2.6661 r₁₆ = −14.4489 d₁₆ = 0.9955  n_(d9) = 1.77250  ν_(d9) = 19.60 r₁₇ = 16.4057 d₁₇ = (Variable) r₁₈ = 29.3239 d₁₈ = 5.3050 n_(d10) = 1.80610 ν_(d10) = 40.74 (Aspheric) r₁₉ = 422.7477 d₁₉ = 0.4857 r₂₀ = 93.3084 d₂₀ = 1.0357 n_(d11) = 1.69895 ν_(d11) = 30.13 r₂₁ = 16.2156 d₂₁ = 5.2656 n_(d12) = 4.49700 ν_(d12) = 81.54 r₂₂ = −38.2018 d₂₂ = (Variable) r₂₃ = −65.0932 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 13.7958 d₂₄ = 2.9478 n_(d14) = 4.84666 ν_(d14) = 23.78 r₂₅ = 19.9898 d₂₅ = (Variable) r₂₆ = 26.7797 d₂₆ = 4.1503 n_(d15) = 1.49700 ν_(d15) = 81.54 (Aspheric) r₂₇ = 33.3863 d₂₇ = 0.1500 r₂₈ = −66.7328 d₂₈ = 4.3835 n_(d16) = 1.61800 ν_(d16) = 63.33 r₂₉ = −18.3728 d₂₉ = 1.0000 n_(d17) = 4.80518 ν_(d17) = 25.42 r₃₀ = 118.1096 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d18) = 4.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d20) = 4.51633 ν_(d20) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 1.7476 × 10⁻⁵  A₆ = 1.7656 × 10⁻⁸  A₈ = 2.5483× 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −7.2819 × 10⁻⁶  A₆ = 1.5490 × 10⁻⁸  A₈ = −1.0251 × 10⁻¹⁰ A₁₀ = 0.0000 26th surface  K = 0  A₄ = −1.2862 × 10⁻⁵  A₆ = −1.1215 × 10⁻⁸  A₈ = 2.6887 × 10⁻¹¹ A₁₀ = = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26000 13.00004 23.30000 41.73010 74.75000 F_(NO) 2.8000 3.2452 3.5000 3.5000 3.5000 ω (°) 38.43 . 13.04 . 4.11 d₆ 1.51813 10.76717 29.84510 47.35892 58.73695 d₁₄ 43.62221 20.67892 10.31138 5.77694 1.73681 d₁₇ 19.34970 13.11504 9.54525 5.96595 0.99829 d₂₂ 2.58148 8.81614 12.38593 15.96522 20.93289 d₂₅ 8.67490 7.43440 5.56358 5.04338 5.18729 d₃₀ 4.28215 5.52265 7.39346 7.91366 7.76975 Example 9  r₁ = 125.4804  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 73.9280  d₂ = 0.6131  r₃ = 82.0053  d₃ = 7.1121  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = −2731.9228  d₄ = 0.2000  r₅ = 73.7403  d₅ = 6.0707  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 689.0297  d₆ = (Variable)  r₇ = 327.5056  d₇ = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 14.2610  d₈ = 8.5253  r₉ = −89.4120  d₉ = 1.3000  n_(d5) = 1.77250  ν_(d5) = 49.60 r₁₀ = 38.2328 d₁₀ = 0.2000  n_(d6) = 1.53508  ν_(d6) = 40.94 r₁₁ = 28.4986 d₁₁ = 2.5230 (Aspheric) r₁₂ = 47.5033 d₁₂ = 1.1790  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = 34.1694 d₁₃ = 3.2934  n_(d8) = 1.84666  ν_(d8) = 23.78 r₁₄ = −324.6493 d₁₄ = (Variable) r₁₅ = ∞ (Stop) d₁₅ = (Variable) r₁₆ = 16.9572 d₁₆ = 7.2692  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₇ = 452.6400 d₁₇ = 0.1000 n_(d10) = 1.80610 ν_(d10) = 40.92 r₁₈ = 136.4678 d₁₈ = 1.1010 n_(d11) = 1.49700 ν_(d11) = 81.54 r₁₉ = 15.7221 d₁₉ = 5.6961 r₂₀ = −38.5697 d₂₀ = (Variable) r₂₁ = 58.4853 d₂₁ = 3.0175 n_(d12) = 1.84666 ν_(d12) = 23.78 r₂₂ = −202.3168 d₂₂ = 1.4952 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₃ = 15.1757 d₂₃ = 8.9786 r₂₄ = −49.4262 d₂₄ = 5.1311 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₅ = −19.2986 d₂₅ = 0.1500 r₂₆ = 18.4543 d₂₆ = 5.9364 n_(d15) = 1.61800 ν_(d15) = 63.33 r₂₇ = −38.6487 d₂₇ = 1.0000 n_(d16) = 1.84666 ν_(d16) = 23.78 r₂₈ = 76.9096 d₂₈ = (Variable) r₂₉ = ∞ d₂₉ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₀ = ∞ d₃₀ = 1.0000 r₃₁ = ∞ d₃₁ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₄ = ∞ d₃₄ = 1.2400 r₃₅ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = −2.9080 × 10⁻⁵  A₆ = −4.7003 × 10⁻⁸  A₈ = 1.3039 × 10⁻¹¹ A₁₀ = 0.0000 16th surface  K = 0  A₄ = −2.6940 × 10⁻⁵  A₆ = −2.6991 × 10⁻⁸  A₈ = −4.1850 × 10⁻¹¹ A₁₀ = 0.0000 24th surface  K = 0  A₄ = 4.8837 × 10⁻⁶  A₆ = 4.0251 × 10⁻⁸  A₈ = 5.0375 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26010 13.00010 23.30000 41.72939 74.74571 F_(NO) 2.8000 3.2311 3.5000 3.5000 3.5000 ω (°) 38.37 . 13.00 . 4.12 d₄ 1.22382 10.57521 30.86112 47.17255 60.33060 d₁₄ 44.41629 22.39761 12.10735 5.55000 2.52402 d₁₅ 18.02944 9.25134 6.75230 3.90933 1.06282 d₂₀ 1.56309 6.26309 10.18795 14.94609 18.74913 d₂₈ 2.00000 5.88418 8.79568 11.11914 9.89434 Example 10  r₁ = 127.5747  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 76.5681  d₂ = 0.6108  r₃ = 87.0503  d₃ = 6.7061  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = −906.1216  d₄ = 0.2000  r₅ = 65.5756  d₅ = 5.1656  n_(d3) = 1.69680  ν_(d3) = 5553  r₆ = 257.9868  d₆ = (Variable)  r₇ = −841.7430  d₇ = 1.7000  n_(d4) = 4.77250  ν_(d4) = 49.60  r₈ = 20.7672  d₈ = 0.1181  n_(d5) = 1.53508  ν_(d5) = 40.94  r₉ = 17.4318  d₉ = 8.3674 (Aspheric) r₁₀ = −69.0347 d₁₀ = 1.3000  n_(d6) = 1.77250  ν_(d6) = 49.60 r₁₁ = 50.8067 d₁₁ = 3.5790 r₁₂ = −34.9364 d₁₂ = 1.2000  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = −206.9525 d₁₃ = 0.7359 r₁₄ = 131.5379 d₁₄ = 2.9312  n_(d8) = 1.68893  ν_(d8) = 31.07 r₁₅ = 65.1273 d₁₅ = 0.2838 r₁₆ = 446.1597 d₁₆ = 3.4504  n_(d9) = 1.84666  ν_(d9) = 23.78 r₁₇ = −111.5214 d₁₇ = (Variable) r₁₈ = −89.0223 d₁₈ = 1.2751 n_(d10) = 1.73400 ν_(d10) = 51.47 r₁₉ = −5156.0079 d₁₉ = 1.0546 r₂₀ = ∞ (Stop) d₂₀ = (Variable) r₂₁ = 20.4978 d₂₁ = 5.4824 n_(d11) = 1.49700 ν_(d11) = 81.54 (Aspheric) r₂₂ = −55.0155 d₂₂ = 0.4103 r₂₃ = 42.1503 d₂₃ = 1.1010 n_(d12) = 1.80610 ν_(d12) = 40.92 r₂₄ = 14.0853 d₂₄ = 5.1806 n_(d13) = 1.49700 ν_(d13) = 81.54 r₂₅ = −75.3872 d₂₅ = (Variable) r₂₆ = −29.7893 d₂₆ = 0.9000 n_(d14) = 1.51633 ν_(d14) = 64.14 r₂₇ = 14.3985 d₂₇ = 3.2881 n_(d15) = 1.84666 ν_(d15) = 23.78 r₂₈ = 28.0747 d₂₈ = (Variable) r₂₉ = 117.1492 d₂₉ = 4.3053 n_(d16) = 1.49700 ν_(d16) = 81.54 (Aspheric) r₃₀ = −21.7875 d₃₀ = 0.1500 r₃₁ = −78.2931 d₃₁ = 5.0168 n_(d17) = 4.61800 ν_(d17) = 133.33 r₃₂ = −14.1145 d₃₂ = 1.0000 n_(d18) = 1.84666 ν_(d18) = 23.78 r₃₃ = −50.2289 d₃₃ = (Variable) r₃₄ = ∞ d₃₄ = 16.0000 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₅ = 1.0000 r₃₆ = ∞ d₃₆ = 2.6000 n_(d20) = 1.547712 ν_(d20) = 62.84 r₃₇ = ∞ d₃₇ = 1.0000 r₃₈ = ∞ d₃₈ = 0.7500 n_(d21) = 1.51633 ν_(d21) = 64.14 r₃₉ = ∞ d₃₉ = 1.2400 r₄₀ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = −1.8060 × 10⁻⁵  A₆ = −1.5653 × 10⁻⁸  A₈ = −3.1402 × 10⁻¹⁰ A₁₀ = 0.0000 21th surface  K = 0  A₄ = −1.9350 × 10⁻⁵  A₆ = 8.1535 × 10⁻⁹  A₈ = −1.1537 × 10⁻¹⁰ A₁₀ = 0.0000 29th surface  K = 0  A₄ = −1.4723 × 10⁻⁵  A₆ = −4.3194 × 10⁻⁹  A₈ = 1.8719 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.26000 13.00000 23.30008 41.73059 74.75291 F_(NO) 2.8000 3.4512 3.5000 3.5000 3.5000 ω (°) 38.48 . 12.85 . 4.11 d₆ 1.64787 10.58883 30.04822 47.11870 58.44456 d₁₇ 44.72174 22.79418 11.48117 5.95085 3.03382 d₂₀ 18.91464 11.56777 8.33111 5.33947 1.07479 d₂₅ 1.84897 8.03143 11.95783 16.13820 22.70498 d₂₈ 8.28264 8.78214 6.88040 5.85483 5.87377 d₃₃ 4.71029 5.37520 6.58719 6.42403 4.10299 Example 11  r₁ = 89.8312  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 63.9685  d₂ = 0.0006  r₃ = 64.1053  d₃ = 9.1675  n_(d2) = 1.49700  νhd d2 = 81.54  r₄ = 79.8472  d₄ = 0.2000  r₅ = 75.2405  d₅ = 6.4325  n_(d3) = 1.60311  ν_(d3) = 60.64  r₆ = 342.9922  d₆ = (Variable)  r₇ = 959.9708  d₇ = 1.8000  n_(d4) = 1.81600  ν_(d4) = 46.62  r₈ = 18.8418  d₈ = 5.3800  r₉ = 472.5238  d₉ = 1.1000  n_(d5) = 1.73400  ν_(d5) = 51.47 r₁₀ = 28.9390 d₁₀ = 5.9081 r₁₁ = −29.2098 d₁₁ = 1.2000  n_(d6) = 171300  ν_(d6) = 53.87 r₁₂ = 100.5460 d₁₂ = 0.1500 r₁₃ = 49.3222 d₁₃ = 7.5695  n_(d7) = 1.63980  ν_(d7) = 34.46 r₁₄ = −24.6810 d₁₄ = (Variable) (Aspheric) r₁₅ = 1133.4292 d₁₅ = 1.2000  n_(d8) = 1.78472  ν_(d8) = 25.68 r₁₆ = 106.5968 d₁₆ = 0.2500 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 20.1552 d₁₈ = 5.1000  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₉ = −94.7419 d₁₉ = 0.1774 r₂₀ = −36.0051 d₂₀ = 1.1410 n_(d10) = 1.80440 ν_(d10) = 39.59 r₂₁ = 13.5064 d₂₁ = 5.5328 n_(d11) = 1.60311 ν_(d11) = 60.64 r₂₂ = −1129.4923 d₂₂ = (Variable) r₂₃ = −72.5596 d₂₃ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₄ = 11.8049 d₂₄ = 2.9338 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₅ = 16.8009 d₂₅ = (Variable) r₂₆ = 91.9126 d₂₆ = 2.9663 n_(d14) = 1.49700 ν_(d14) = 81.54 r₂₇ = 29.0231 d₂₇ = 0.1500 (Aspheric) r₂₈ = 48.8627 d₂₈ = 5.1022 n_(d15) = 1.60311 ν_(d15) = 60.64 r₂₉ = −13.3197 d₂₉ = 0.8500 n_(d16) = 1.84666 ν_(d16) = 23.78 r₃₀ = −48.0006 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 14th surface  K = 0  A₄ = −8.9550 × 10⁻⁹  A₆ = 8.4748 × 10⁻⁹  A₈ = 1.6761 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −1.7592 × 10⁻⁵  A₆ = 4.4455 × 10⁻⁹  A₈ = −1.3451 × 10⁻¹⁰ A₁₀ = 0.0000 27th surface  K = 0  A₄ = −1.4716 × 10⁻⁶  A₆ = 1.5442 × 10⁻⁹  A₈ = −2.3629 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.33845 13.10321 23.28940 38.89145 74.68837 F_(NO) 2.8000 3.1859 3.5000 3.5000 3.5000 ω (°) 38.12 . 13.01 . 4.08 d₆ 1.36006 12.64030 31.07482 48.17964 61.33273 d₁₄ 54.26370 25.04693 11.10499 5.19824 1.70314 d₁₇ 17.41698 12.14210 8.86214 6.81538 1.02608 d₂₂ 1.50000 4.14980 6.85803 9.34039 16.90092 d₂₅ 6.85640 7.47895 6.17972 5.74352 6.81559 d₃₀ 4.46020 7.59229 8.38310 9.82468 5.35600 Example 12  r₁ = 82.2399  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 60.0259  d₂ = 0.1000  r₃ = 60.6829  d₃ = 7.7500  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 307.4605  d₄ = 0.2000  r₅ = 72.7643  d₅ = 5.8500  n_(d3) = 1.60311  ν_(d3) = 60.64  r₆ = 328.6935  d₆ = (Variable)  r₇ = 266.6699  d₇ = 1.8000  n_(d4) = 1.81600  ν_(d4) = 16.62  r₈ = 18.3068  d₈ = 6.0269  r₉ = −91.9091  d₉ = 1.1000  n_(d5) = 1.73400  ν_(d5) = 51.47 r₁₀ = 31.9296 d₁₀ = 5.1735 r₁₁ = −33.4696 d₁₁ = 1.2000  n_(d6) = 1.71300  ν_(d6) = 53.87 (Aspheric) r₁₂ = 1.387 × 10⁴ d₁₂ = 0.1500 r₁₃ = 76.1645 d₁₃ = 6.2143  n_(d7) = 1.69895  ν_(d7) = 30.13 r₁₄ = −29.0944 d₁₄ = (Variable) r₁₅ = −256.8086 d₁₅ = 1.0000  n_(d8) = 1.78472  ν_(d8) = 25.68 r₁₆ = 217.7610 d₁₆ = 0.2030 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 19.3410 d₁₈ = 15.5508  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₉ = 61.9647 d₁₉ = 0.1774 r₂₀ = 28.8671 d₂₀ = 1.1410 n_(d10) = 1.80440 ν_(d10) = 39.59 r₂₁ = 13.5945 d₂₁ = 5.8000 n_(d11) = 1.49700 ν_(d11) = 81.54 r₂₂ = 5392.6719 d₂₂ = (Variable) r₂₃ = −154.6780 d₂₃ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₄ = 11.7076 d₂₄ = 3.6031 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₅ = 15.0847 d₂₅ = (Variable) r₂₆ = 50.4757 d₂₆ = 3.2775 n_(d14) = 1.49700 ν_(d14) = 81.54 r₂₇ = −50.8313 d₂₇ = 0.1500 (Aspheric) r₂₈ = −45.8348 d₂₈ = 5.5505 n_(d15) = 1.60311 ν_(d15) = 60.64 r₂₉ = −13.2011 d₂₉ = 0.8500 n_(d16) = 1.84666 ν_(d16) = 23.78 r₃₀ = −38.4178 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d18) = 4.54771 ν_(d18) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 2.1955 × 10⁻⁶  A₆ = 7.9776 × 10⁻¹⁰  A₈ = 4.2465 × 10⁻¹² A₁₀ = 0.0000 18th surface  K = 0  A₄ = −2.2173 × 10⁻⁵  A₆ = −5.2442 × 10⁻¹⁰  A₈ = −1.3172 × 10⁻¹⁰ A₁₀ = 0.0000 27th surface  K = 0  A₄ = −4 3385 × 10⁻⁶  A₆ = −5.8507 × 10⁻⁹  A₈ = −3.8312 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.35253 13.14155 23.30044 40.58970 74.68803 F_(NO) 2.8000 3.1943 3.5000 3.5000 3.5000 ω (°) 38.09 . 13.06 . 4.10 d₆ 1.36006 12.88245 31.00495 49.05687 59.99418 d₁₄ 52.40573 25.29926 11.47801 5.29211 1.70314 d₁₇ 17.47445 12.09215 9.07829 6.89688 1.02608 d₂₂ 1.50000 3.82243 6.29079 8.72220 16.22424 d₂₅ 6.18879 6.98900 5.58223 5.34260 5.88322 d₃₀ 1.19155 7.72421 5.35600 9.52720 3.22100 Example 13  r₁ = 128.1845  d₁ = 2.6000  n_(d1) = 4.84666  ν_(d1) = 23.78  r₂ = 77.8836  d₂ = 0.1422  r₃ = 79.5351  d₃ = 8.7726  n_(d2) = 1.60311  ν_(d2) = 60.64  r₄ = 1.760 × 105  d₄ = 0.2000  r₅ = 60.5207  d₅ = 7.8199  n_(d3) = 4.49700  ν_(d3) = 81.54  r₆ = 225.3888  d₆ = (Variable)  r₇ = 87.0813  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 15.7852  d₈ = 8.9335  r₉ = −28.4093  d₉ = 1.3643  n_(d5) = 4.77250  ν_(d5) = 49.60 r₁₀ = 61.5066 d₁₀ = 2.4804 r₁₁ = −48.6469 d₁₁ = 0.2000  n_(d6) = 4.53508  ν_(d6) = 40.94 (Aspheric) r₁₂ = −200.0000 d₁₂ = 1.2000  n_(d7) = 1.693502  ν_(d7) = 53.20 r₁₃ = 96.2114 d₁₃ = 0.2000 r₁₄ = 68.6685 d₁₄ = 6.7199  n_(d8) = 1.68893  ν_(d8) = 31.07 r₁₅ = −32.7420 d₁₅ = (Variable) r₁₆ = ∞ (Stop) d₁₆ = 0.4000 r₁₇ = 312.4731 d₁₇ = 0.9972  n_(d9) = 1.60342  ν_(d9) = 38.03 r₁₈ = −144.3938 d₁₈ = (Variable) r₁₉ = 18.9253 d₁₉ = 3.6985 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₂₀ = −1.054 × 10⁷ d₂₀ = 0.1774 r₂₁ = 58.8544 d₂₁ = 1.1208 n_(d11) = 1.77250 ν_(d11) = 49.60 r₂₂ = 15.9897 d₂₂ = 4.9136 n_(d12) = 1.49700 ν_(d12) = 81.54 r₂₃ = −68.6413 d₂₃ = (Variable) r₂₄ = −73.7867 d₂₄ = 0.9000 n_(d13) = 1.516332 ν_(d13) = 64.14 r₂₅ = 17.0943 d₂₅ = 1.8262 n_(d14) = 1.846661 ν_(d14) = 23.78 r₂₆ = −22.4714 d₂₆ = (Variable) r₂₇ = 37.0884 d₂₇ = 4.8733 n_(d15) = 1.49700 ν_(d15) = 81.54 (Aspheric) r₂₈ = −23.1086 d₂₈ = 0.1500 r₂₉ = −909.2556 d₂₉ = 3.3951 n_(d16) = 1.49700 ν_(d16) = 81.54 r₃₀ = −18.5310 d₃₀ = 1.0265 n_(d17) = 1.84666 ν_(d17) = 23.78 r₃₁ = −50.0749 d₃₁ = (Variable) r₃₂ = ∞ d₃₂ = 16.0000 n_(d18) = 1.51633 ν_(d18) = 64.14 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₅ = ∞ d₃₅ = 1.0000 r₃₆ = ∞ d₃₆ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₇ = ∞ d₃₇ = 1.2400 r₃₈ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 9.2934 × 10⁻⁶  A₆ = −4.3005 × 10⁻⁹  A₈ = −6.0577 × 10⁻¹⁰ A₁₀ = 0.0000 19th surface  K = 0  A₄ = −1.5515 × 10⁻⁵  A₆ = −1.5901 × 10⁻⁹  A₈ = −1.9683 × 10⁻¹⁰ A₁₀ = 0.0000 27th surface  K = 0  A₄ = −1.7557 × 10⁻⁵  A₆ = −2.2661 × 10⁻⁹  A₈ = 1.2023 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.27699 13.13483 23.30156 41.85838 74.69868 F_(NO) 2.8000 3.0096 3.5000 3.5000 3.5000 ω (°) 38.47 . 13.07 . 4.13 d₆ 1.00000 12.32463 29.12057 47.14255 58.02772 d₁₅ 6.72043 27.00532 13.69308 7.48255 2.50000 d₁₈ 20.38443 13.68554 10.29674 7.22603 1.55935 d₂₃ 0.86734 3.00362 6.20380 8.91257 14.79711 d₂₆ 7.49819 8.31394 5.77953 5.09499 5.49059 d₃₁ 5.53190 9.13816 11.98670 8.63592 12.42630 Example 14  r₁ = 117.1093  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 78.9815  d₂ = 0.2900  r₃ = 83.6308  d₃ = 7.1360  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 8.136 × 10⁻⁴  d₄ = 0.2000  r₅ = 64.0026  d₅ = 7.2854  n_(d3) = 1.49700  ν_(d3) = 81.54  r₆ = 406.9074  d₆ = (Variable)  r₇ = 173.0596  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 19.60  r₈ = 14.7807  d₈ = 8.6963  r₉ = 33.4479  d₉ = 1.3643  n_(d5) = 1.77250  ν_(d5) = 19.60 r₁₀ = 82.7642 d₁₀ = 1.5769 r₁₁ = −78.1187 d₁₁ = 20.4088  n_(d6) = 1.66680  ν_(d6) = 33.05 (Aspheric) r₁₂ = 518.9177 d₁₂ = 1.2000  n_(d7) = 1.69350  ν_(d7) = 53.20 r₁₃ = −55.8817 d₁₃ = 0.0065 r₁₄ = 43.1420 d₁₄ = 5.9081  n_(d8) = 1.68893  ν_(d8) = 31.07 r₁₅ = −31.8050 d₁₅ = (Variable) r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 21.9025 d₁₇ = 3.3063  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = 1.082 × 10⁶ d₁₈ = 0.2991 r₁₉ = 30.2359 d₁₉ = 1.1208 n_(d10) = 1.77250 ν_(d10) = 49.60 r₂₀ = 14.9061 d₂₀ = 5.0481 n_(d11) = 4.49700 ν_(d11) = 81.54 r₂₁ = −81.9434 d₂₁ = (Variable) r₂₂ = −101.2030 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = −15.4168 d₂₃ = 1.8234 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₄ = 20.2251 d₂₄ = (Variable) r₂₅ = 42.9650 d₂₅ = 4.1635 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −21.2353 d₂₆ = 0.1500 r₂₇ = −231.8094 d₂₇ = 2.6973 n_(d15) = 1.49700 ν_(d15) = 81.54 r₂₈ = −16.2244 d₂₈ = 1.2276 n_(d16) = 4.84666 ν_(d16) = 23.78 r₂₉ = −47.0800 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 4.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₅ = 1.2400 r₃₆ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 8.8203 × 10⁻⁶  A₆ = 9.5199 × 10⁻⁹  A₈ = −4.6923 × 10⁻¹¹ A₁₀ = 0.0000 17th surface  K = 0  A₄ = −1.2806 × 10⁻⁵  A₆ = −2.1296 × 10⁻⁹  A₈ = −2.5132 × 10⁻¹¹ A₁₀ = 0.0000 25th surface  K = 0  A₄ = −1.7844 × 10⁻⁵  A₆ = 8.4598 × 10⁻¹⁰  A₈ = 1.3070 × 10¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.33668 13.24737 23.30078 42.13815 74.69414 F_(NO) 2.8000 3.0902 3.5000 3.5000 3.5000 ω (°) 38.27 . 13.00 . 4.12 d₆ 1.00000 11.42124 30.94061 48.29039 59.30210 d₁₅ 55.59662 25.85692 13.75365 6.56339 2.50000 d₁₆ 20.18772 14.53075 11.35844 7.51283 1.55935 d₂₁ 2.76426 4.80624 7.15711 10.16404 16.30729 d₂₄ 7.71856 7.83389 6.04720 4.97905 4.27440 d₂₉ 4.70560 8.31100 10.79320 8.56974 13.14420 Example 15  r₁ = 132.6548  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 79.4364  d₂ = 0.4361  r₃ = 85.8501  d₃ = 6.6634  n_(d2) = 1.60311  ν_(d2) = 60.64  r₄ = 4.060 × 10⁴  d₄ = 0.2000  r₅ = 59.6705  d₅ = 6.1756  n_(d3) = 1.497002  ν_(d3) = 81.54  r₆ = 294.2591  d₆ = (Variable)  r₇ = 98.7402  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 14.8930  d₈ = 9.4296  r₉ = −32.3971  d₉ = 1.3643  n_(d5) = 1.77250  ν_(d5) = 19.60 r₁₀ = 70.8620 d₁₀ = 2.0091 r₁₁ = −72.3210 d₁₁ = 0.2000  n_(d6) = 1.53508  ν_(d6) = 10.94 (Aspheric) r₁₂ = −200.0000 d₁₂ = 1.2000  n_(d7) = 1.69350  ν_(d7) = 53.20 r₁₃ = 67.0853 d₁₃ = 0.2000 r₁₄ = 44.8428 d₁₄ = 6.9613  n_(d8) = 1.68893  ν_(d8 −31.07) r₁₅ = −35.6841 d₁₅ = (Variable) r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 21.0081 d₁₇ = 2.9255  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −9.840 × 10⁻⁵ d₁₈ = 0.1774 r₁₉ = 34.1654 d₁₉ = 1.1208 n_(d10) = 1.77250 ν_(d10) = 49.60 r₂₀ = 14.0687 d₂₀ = 4.9352 n_(d11) = 4.49700 ν_(d11) = 81.54 r₂₁ = −74.9646 d₂₁ = (Variable) r₂₂ = −61.8007 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = 16.0108 d₂₃ = 1.8375 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₄ = 22.5570 d₂₄ = (Variable) r₂₅ = 32.5943 d₂₅ = 4.3313 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −33.8655 d₂₆ = 0.1500 r₂₇ = 53.1963 d₂₇ = 1.1524 n_(d15) = 1.84666 ν_(d15) = 23.78 r₂₈ = 18.3125 d₂₈ = 3.6734 n_(d16) = 4.49700 ν_(d16) = 81.54 r₂₉ = −121.7913 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 6.0000 n_(d17) = 4.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₅ = 1.2400 Aspherical Coefficients 11th surface  K = 0  A₄ = = 5.6253 × 10⁻⁶  A₆ = = 8.1204 × 10⁻⁹  A₈ = −1.5465 × 10⁻¹⁰ A₁₀ = = 0.0000 17th surface  K = 0  A₄ = −1.0911 × 10⁻⁵  A₆ = −8.6347 × 10⁻¹⁰  A₈ = −3.2657 × 10⁻¹¹ A₁₀ = 0.0000 25th surface  K = 0  A₄ = −1.8333 × 10⁻⁵  A₆ = −3.1998 × 10⁻⁹  A₈ = 1.0415 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W WS S ST T f (mm) 7.28638 13.09183 23.29942 41.55110 74.69787 F_(NO) 2.8000 3.0933 3.5000 3.5000 3.5000 ω (°) 38.41 . 13.04 . 4.13 d₆ 1.00000 12.01687 29.52891 47.09799 58.40761 d₁₅ 56.60227 27.25102 13.50469 7.09969 2.50000 d₁₆ 20.20946 14.09927 10.84298 7.36903 1.55935 d₂₁ 2.22975 4.07145 6.73846 9.29928 14.66227 d₂₄ 8.05739 8.70338 6.54360 6.01591 6.08811 d₂₉ 6.19420 9.22330 12.55330 8.60639 14.38620 Example 16  r₁ = 80.0460  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 57.3690  d₂ = 0.0798  r₃ = 56.8758  d₃ = 6.9751  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 362.0517  d₄ = 0.2000  r₅ = 73.3775  d₅ = 4.4654  n_(d3) = 1.60311  ν_(d3) = 60.64  r₆ = 289.7112  d₆ = (Variable)  r₇ = 177.0825  d₇ = 1.5000  n_(d4) = 1.77250  ν_(d4) = 19.60  r₈ = 16.8427  d₈ = 7.9000  r₉ = −29.2679  d₉ = 1.3643  n_(d5) = 1.77250  ν_(d5) = 19.60 (Aspheric) r₁₀ = 67.6142 d₁₀ = 3.5642 r₁₁ = 117.8157 d₁₁ = 4.8943  n_(d6) = 1.72825  ν_(d6) = 28.46 r₁₂ = −31.3298 d₁₂ = 0.5000 r₁₃ = 63.4774 d₁₃ = 1.0000  n_(d7) = 1.74400  ν_(d7) = 14.78 r₁₄ = −239.8825 d₁₄ = (Variable) r₁₅ = −435.4231 d₁₅ = 1.2680  n_(d8) = 1.72825  ν_(d8) = 28.46 r₁₆ = −514.6994 d₁₆ = 1.3139 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 20.0387 d₁₈ = 5.6776  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₉ = −73.1240 d₁₉ = 0.1774 r₂₀ = 46.3298 d₂₀ = 1.1410 n_(d10) = 1.80440 ν_(d10) = 39.59 r₂₁ = −13.8759 d₂₁ = 5.4223 n_(d11) = 1.60311 ν_(d11) = 60.64 r₂₂ = −120.0020 d₂₂ = (Variable) r₂₃ = −55.7471 d₂₃ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₄ = 11.2108 d₂₄ = 1.8651 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₅ = 15.9872 d₂₅ = (Variable) r₂₆ = 55.1052 d₂₆ = 2.9459 n_(d14) = 1.49700 ν_(d14) = 81.54 r₂₇ = −28.6459 d₂₇ = 0.1500 (Aspheric) r₂₈ = −69.1964 d₂₈ = 4.5501 n_(d15) = 1.60311 ν_(d15) = 60.64 r₂₉ = −13.8791 d₂₉ = 1.0000 n_(d16) = 1.84666 ν_(d16) = 23.78 r₃₀ = −46.4615 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d18) = 1.547712 ν_(d18) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d19) = 1.516332 ν_(d19) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 8.8395 × 10⁻⁶  A₆ = 5.0711 × 10⁻⁹  A₈ = −1.9545 × 10⁻¹¹ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −2.0678 × 10⁻⁵  A₆ = −6.4243 × 10⁻⁹  A₈ = 2.3028 × 10⁻¹¹ A₁₀ = 0.0000 27th surface  K = 0  A₄ = −3.0971 × 10⁻⁶  A₆ = −9.4407 × 10⁻⁹  A₈ = 1.9644 × 10⁻¹¹ A₁₀ = 0.0000 Zooming Data (∞) W S T f (mm) 7.27185 23.29749 74.69992 F_(NO) 2.8000 3.5000 3.5000 ω (°) 40.17 13.97 4.40 d₆ 1.36006 30.12912 58.31748 d₁₄ 54.70456 12.24625 1.70314 d₁₇ 17.26301 9.52391 1.02608 d₂₂ 1.50000 6.53585 16.09191 d₂₅ 7.85799 6.35824 6.81641 d₃₀ 4.64000 8.84600 7.32400 Example 17  r₁ = 84.5614  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 60.9235  d₂ = 0.1000  r₃ = 60.9993  d₃ = 7.7500  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 411.3180  d₄ = 0.2000  r₅ = 69.8137  d₅ = 5.8500  n_(d3) = 1.603111  ν_(d3) = 60.64  r₆ = 273.9185  d₆ = (Variable)  r₇ = 326.8029  d₇ = 1.8000  n_(d4) = 1.816002  ν_(d4) = 46.62  r₈ = 18.4614  d₈ = 5.8823  r₉ = −86.8945  d₉ = 1.1000  n_(d5) = 4.734002  ν_(d5) = 51.47 r₁₀ = 32.9914 d₁₀ = 5.2210 r₁₁ = −30.1936 d₁₁ = 1.2000  n_(d6) = 1.71300  ν_(d6) = 53.87 (Aspheric) r₁₂ = 3.111 × 10⁴ d₁₂ = 0.1500 r₁₃ = 94.9186 d₁₃ = 6.1767  n_(d7) = 71.69895  ν_(d7) = 30.13 r₁₄ = 27.0373 d₁₄ = (Variable) r₁₅ = −754.3167 d₁₅ = 0.8000  n_(d8) = 1.784721  ν_(d8) = 25.68 r₁₆ = 50.7584 d₁₆ = 2.0000  n_(d9) = 1.68893  ν_(d9) = 31.07 r₁₇ = 699.9122 d₁₇ = 0.7000 r₁₈ = ∞ (Stop) d₁₈ = (Variable) r₁₉ = 19.3389 d₁₉ = 5.5976 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₂₀ = −64.3089 d₂₀ = 0.1774 r₂₁ = −36.8090 d₂₁ = 1.1410 n_(d11) = 1.80440 ν_(d11) = 39.59 r₂₂ = 15.7560 d₂₂ = 4.3000 n_(d12) = 1.49700 ν_(d12) = 81.54 r₂₃ = 6909.3107 d₂₃ = (Variable) r₂₄ = −213.9678 d₂₄ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₅ = 11.9504 d₂₅ = 3.6757 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₆ = −15.7330 d₂₆ = (Variable) r₂₇ = 56.9085 d₂₇ = 3.2663 n_(d15) = 1.49700 ν_(d15) = 81.54 r₂₈ = −49.9335 d₂₈ = 0.1500 (Aspheric) r₂₉ = 48.3454 d₂₉ = 5.3103 n_(d16) = 1.60311 ν_(d16) = 60.64 r₃₀ = −12.9112 d₃₀ = 0.8500 n_(d17) = 1.84666 ν_(d17) = 23.78 r₃₁ = −36.0617 d₃₁ = (Variable) r₃₂ = ∞ d₃₂ = 16.0000 n_(d18) = 1.51633 ν_(d18) = 64.14 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₅ = ∞ d₃₅ = 1.0000 r₃₆ = ∞ d₃₆ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₇ = ∞ d₃₇ = 1.2400 r₃₈ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 3.5442 × 10⁻⁶  A₆ = −1.0145 × 10⁻⁸  A₈ = 4.1292 × 10⁻¹¹ A₁₀ = 0.0000 19th surface  K = 0  A₄ = −2.3122 × 10⁻⁵  A₆ = −1.0925 × 10⁻⁹  A₈ = −1.2640 × 10⁻¹⁰ A₁₀ = 0.0000 28th surface  K = 0  A₄ = −2.8818 × 10⁻⁶  A₆ = −5.4227 × 10⁻⁹  A₈ = −2.8339 × 10⁻¹⁰ A₁₀ = = 0.0000 Zooming Data (∞) W S T f (mm) 7.27212 23.29915 74.69940 F_(NO) 2.8000 3.5000 3.5000 ω (°) 38.44 13.06 4.09 d₆ 1.36006 31.23645 59.54246 d₁₄ 52.32231 11.30384 1.70314 d₁₈ 17.20275 8.82296 1.02608 d₂₃ 1.50000 6.61710 16.48589 d₂₆ 6.17485 5.37142 6.39230 d₃₁ 2.40000 6.46400 3.36900 Example 18  r₁ = 85.6717  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 61.4682  d₂ = 0.1000  r₃ = 61.7093  d₃ = 7.7500  n_(d2) = 4.49700  ν_(d2) = 81.54  r₄ = 391.3879  d₄ = 0.2000  r₅ = 71.8120  d₅ = 5.8500  n_(d3) = 1.60311  ν_(d3) = 30.64  r₆ = 318.2499  d₆ = (Variable)  r₇ = 360.3572  d₇ = 1.8000  n_(d4) = 4.81600  ν_(d4) = 46.62  r₈ = 18.8770  d₈ = 5.9565  r₉ = −91.8447  d₉ = 1.1000  n_(d5) = 1.73400  ν_(d5) = 51.47 r₁₀ = 33.5783 d₁₀ = 5.2551 r₁₁ = −31.3548 d₁₁ = 1.2000  n_(d6) = 1.71300  ν_(d6) = 53.87 (Aspheric) r₁₂ = 4.805 × 104 d₁₂ = 0.1500 r₁₃ = 97.5840 d₁₃ = 6.2516  n_(d7) = 1.69895  ν_(d7) = 30.13 r₁₄ = −27.8035 d₁₄ = (Variable) r₁₅ = ∞ d₁₅ = 1.8000  n_(d8) = 4.78472  ν_(d8) = 25.68 r₁₆ = 268.7641 d₁₆ = 1.0000 (Aspheric) r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 18.6304 d₁₈ = 5.6253  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₉ = −57.6238 d₁₉ = 0.1774 r₂₀ = 34.9774 d₂₀ = 1.1410 n_(d10) = 1.80440 ν_(d10) = 39.59 r₂₁ = 14.9385 d₂₁ = 4.3000 n_(d11) = 1.49700 ν_(d11) = 81.54 r₂₂ = 4295.3319 d₂₂ = (Variable) r₂₃ = −226.3830 d₂₃ = 0.9000 n_(d12) = 4.51633 ν_(d12) = 64.14 r₂₄ = 11.9132 d₂₄ = 3.6481 n_(d13) = 4.84666 ν_(d13) = 23.78 r₂₅ = 15.2759 d₂₅ = (Variable) r₂₆ = 54.3162 d₂₆ = 3.3130 n_(d14) = 4.49700 ν_(d14) = 81.54 r₂₇ = −51.5747 d₂₇ = 0.1500 (Aspheric) r₂₈ = 49.4131 d₂₈ = 5.2625 n_(d15) = 4.60311 ν_(d15) = 60.64 r₂₉ = −13.1129 d₂₉ = 0.8500 n_(d16) = 1.84666 ν_(d16) = 23.78 r₃₀ = −36.5139 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d29) = 1.51633 ν_(d19) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 11th surface  K = 0  A₄ = 3.5400 × 10⁻⁶  A₆ = −7.6377 × 10⁻⁹  A₈ = 4.0209 × 10⁻¹¹ A₁₀ = 0.0000 16th surface  K = 0  A₄ = −4.0343 × 10⁻⁷  A₆ = 2.7672 × 10⁻⁸  A₈ = −2.5380 × 10⁻¹⁰ A₁₀ = 0.0000 18th surface  K = 0  A₄ = −2.6388 × 10⁻⁵  A₆ = −1.7329 × 10⁻⁹  A₈ = −1.6305 × 10⁻¹⁰ A₁₀ = 0.0000 27th surface  K = 0  A₄ = −3.4938 × 10⁻⁶  A₆ = −5.9935 × 10⁻⁹  A₈ = −2.8356 × 10⁻¹⁰ A₁₀ = = 0.0000 Zooming Data (∞) W S T f (mm) 7.27244 23.30032 74.70039 F_(NO) 2.8000 3.5000 3.5000 ω (°) 38.45 13.05 4.09 d₆ 1.36006 31.15403 59.61613 d₁₄ 52.28998 11.32834 1.70314 d₁₇ 17.27794 8.92919 1.02608 d₂₂ 1.50000 6.44912 16.47111 d₂₅ 6.18489 5.46432 6.07561 d₃₀ 2.39700 6.50900 3.82700 Example 19  r₁ = 102.8951  d₁ = 2.2000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 61.5389  d₂ = 11.0000  n_(d2) = 1.49700  ν_(d2) = 81.54  r₃ = −641.2805  d₃ = 0.2750  r₄ = 51.4180  d₄ = 6.1875  n_(d3) = 1.69680  ν_(d3) = 55.53  r₅ = 146.6226  d₅ = (Variable)  r₆ = 148.7220  d₆ = 1.9010  n_(d4) = 1.83400  ν_(d4) = 37.16  r₇ = 15.1960  d₇ = 8.2500  r₈ = −17.1556  d₈ = 1.6500  n_(d5) = 1.80610  ν_(d5) = 40.92  r₉ = 15.0399  d₉ = 2.0625 (Aspheric) r₁₀ = 58.8129 d₁₀ = 3.4375  n₆ = 1.68893  ν_(d6) = 31.07 r₁₁ = −74.3150 d₁₁ = 0.2062 r₁₂ = 241.0544 d₁₂ = 4.8125  n_(d7) = 1.68893  ν_(d7) = 31.07 r₁₃ = −21.3830 d₁₃ = (Variable) r₁₄ = ∞ (Stop) d₁₄ = (Variable) r₁₅ = 37.4279 d₁₅ = 3.4375  n₈ = 1.49700  ν_(d8) = 81.54 (Aspheric) r₁₆ = −462.8778 d₁₆ = 0.2062 r₁₇ = 15.8702 d₁₇ = 5.5000  n_(d9) = 1.59551  ν_(d9) = 39.24 r₁₈ = 79.4628 d₁₈ = 1.3750 n_(d10) = 1.80610 ν_(d10) = 40.92 r₁₉ = 14.4884 d₁₉ = (Variable) r₂₀ = 26.6553 d₂₀ = 4.1250 n_(d11) = 1.83400 ν_(d11) = 37.16 r₂₁ = 147.2888 d₂₁ = 0.4125 r₂₂ = 142.7176 d₂₂ = 1.3750 n_(d12) = 1.84666 ν_(d12) = 23.78 r₂₃ = −17.8989 d₂₃ = 6.1875 n_(d13) = 1.49700 ν_(d13) = 81.54 r₂₄ = −22.9886 d₂₄ = (Variable) (Aspheric) r₂₅ = ∞ d₂₅ = 23.3750 n_(d14) = 1.51633 ν_(d14) = 64.14 r₂₆ = ∞ d₂₆ = 1.3750 r₂₇ = ∞ d₂₇ = 2.2000 n_(d15) = 1.54771 ν_(d15) = 62.84 r₂₈ = ∞ d₂₈ = 1.3750 r₂₉ = ∞ d₂₉ = 1.0313 n_(d16) = 4.52300 ν_(d16) = 55.00 r₃₀ = ∞ d₃₀ = 3.2468 r₃₁ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = −1.4335 × 10⁻⁴  A₆ = 3.6008 × 10⁻⁷  A₈ = −1.5707 × 10⁻⁹ A₁₀ = 0.0000 15th surface  K = 0  A₄ = −8.3514 × 10⁻⁶  A₈ = −6.4776 × 10⁻¹⁰  A₈ = −1.3217 × 10⁻¹¹ A₁₀ = 0.0000 24th surface  K = 20  A₄ = 2.1082 × 10⁻⁵  A₆ = 9.2526 × 10⁻⁸  A₈ = −1.4509 × 10⁻⁹ A₁₀ = 6.8600 × 10⁻¹² Zooming Data (∞) W S T f (mm) 7.15436 18.83672 50.05002 F_(NO) 2.0482 2.3536 2.5012 ω (°) 38.38 15.78 6.16 d₅ 1.37500 23.10024 44.56543 d₁₃ 53.62605 19.09389 6.13762 d₁₄ 23.19509 10.31787 3.56923 d₁₉ 7.00580 12.70882 18.49477 d₂₄ 1.19821 7.55450 9.33878 Example 20  r₁ = 155.9824  d₁ = 1.7875  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 61.8424  d₂ = 11.0000  n_(d2) = 1.61800  ν_(d2) = 63.33  r₃ = −600.9530  d₃ = 0.2750  r₄ = 47.5178  d₄ = 6.1875  n_(d3) = 4.69680  ν_(d3) = 55.53  r₅ = 121.5999  d₅ = (Variable)  r₆ = 119.2914  d₆ = 1.3750  n_(d4) = 1.80610  ν_(d4) = 40.92  r₇ = 13.2227  d₇ = 8.2500 (Aspheric)  r₈ = −32.4710  d₈ = 1.6500  n_(d5) = 1.83400  ν_(d5) = 37.16  r₉ = 39.0123  d₉ = 1.3750 r₁₀ = 165.6443 d₁₀ = 1.3750  n_(d6) = 1.57501  ν_(d6) = 41.50 r₁₁ = 20.0406 d₁₁ = 7.1500  n_(d7) = 1.75520  ν_(d7) = 27.51 r₁₂ = −48.8507 d₁₂ = (Variable) r₁₃ = ∞ (Stop) d₁₃ = (Variable) r₁₄ = 30.8548 d₁₄ = 3.4375  n_(d8) = 1.80518  ν_(d8) = 25.42 r₁₅ = 89.0085 d₁₅ = 0.2062 r₁₆ = 38.9337 d₁₆ = 4.4000  n_(d9) = 1.80610  ν_(d9) = 40.92 (Aspheric) r₁₇ = −94.3851 d₁₇ = 1.3750 n_(d10) = 1.84666 ν_(d10) = 23.78 r₁₈ = 32.5308 d₁₈ = (Variable) r₁₉ = −57.6645 d₁₉ = 2.7500 n_(d11) = 1.77250 ν_(d11) = 49.60 r₂₀ = −47.1601 d₂₀ = 1.3750 n_(d12) = 1.60342 ν_(d12) = 38.03 r₂₁ = 30.6668 d₂₁ = (Variable) r₂₂ = −228.3337 d₂₂ = 1.3750 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₃ = 19.0716 d₂₃ = 6.1875 n_(d14) = 1.497002 ν_(d14) = 81.54 r₂₄ = −31.2823 d₂₄ = 0.2062 (Aspheric) r₂₅ = 36.1622 d₂₅ = 6.1875 n_(d15) = 21.69350 ν_(d15) = 53.21 r₂₆ = −35.8359 d₂₆ = (Variable) r₂₇ = ∞ d₂₇ = 23.3750 n_(d16) = 1.51633 ν_(d16) = 64.14 r₂₈ = ∞ d₂₈ = 1.3750 r₂₉ = ∞ d₂₉ = 2.2000 n_(d17) = 1.54771 ν_(d17) = 62.84 r₃₀ = ∞ d₃₀ = 1.3750 r₃₁ = ∞ d₃₁ = 1.0313 n_(d18) = 1.52300 ν_(d18) = 55.00 r₃₂ = ∞ d₃₂ = 3.2377 r₃₃ = ∞ Aspherical Coefficients 7th surface  K = 0  A₄ = −2.0811 × 10⁻⁵  A₆ = −9.3584 × 10⁻¹⁰  A₈ = −9.2039 × 10⁻¹⁰ A₁₀ = 0.0000 16th surface  K = 0  A₄ = −9.0277 × 10⁻⁶  A₆ = 2.1013 × 10⁻⁸  A₈ = −5.4554 × 10⁻¹⁰ A₁₀ = 2.6012 × 10⁻¹² 24th surface  K = 0  A₄ = −1.8657 × 10⁻⁶  A₆ = 2.3003 × 10⁻⁸  A₈ = −5.0119 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W S T f (mm) 7.16206 18.83631 50.04733 F_(NO) 2.0290 2.3673 2.8226 ω (°) 38.34 15.98 6.16 d₅ 1.37500 20.39279 42.36136 d₁₂ 49.98780 14.95968 7.89768 d₁₃ 20.74150 12.47266 4.81483 d₁₈ 2.75692 5.61404 10.58915 d₂₁ 7.73772 5.38351 6.87877 d₂₆ 2.75000 9.90480 11.70852 Example 21  r₁ = 104.3405  d₁ = 2.2000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 59.5725  d₂ = 11.0000  n_(d2) = 1.49700  ν_(d2) = 81.54  r₃ = 4321.3547  d₃ = 0.2750  r₄ = 47.5960  d₄ = 6.1875  n_(d3) = 1.69680  ν_(d3) = 55.53  r₅ = 136.8909  d₅ = (Variable)  r₆ = 140.6680  d₆ = 1.9010  n_(d4) = 1.80610  ν_(d4) = 40.92  r₇ = 13.7491  d₇ = 6.1875 (Aspheric)  r₈ = −60.0958  d₈ = 1.6500  n_(d5) = 1.83400  ν_(d5) = 37.16  r₉ = 61.9207  d₉ = 4.1250 r₁₀ = −21.5206 d₁₀ = 1.3750  n_(d6) = 1.63930  ν_(d6) = 44.87 r₁₁ = 56.5075 d₁₁ = 3.4375 r₁₂ = 96.6074 d₁₂ = 5.5000  n_(d7) = 1.80100  ν_(d7) = 34.97 r₁₃ = −25.9673 d₁₃ = (Variable) r₁₄ = ∞ (Stop) d₁₄ = 2.7500 r₁₅ = −40.0734 d₁₅ = 1.2375  n_(d8) = 1.60311  ν_(d8) = 60.64 r₁₆ = 78.4453 d₁₆ = (Variable) r₁₇ = 34.7554 d₁₇ = 4.8125  n_(d9) = 1.80809  ν_(d9) = 22.76 r₁₈ = 1028.4306 d₁₈ = 0.2062 r₁₉ = 60.9355 d₁₉ = 4.4000 n_(d10) = 1.80610 ν_(d10) = 40.92 (Aspheric) r₂₀ = −29.1117 d₂₀ = 1.3750 n_(d11) = 1.84666 ν_(d11) = 23.78 r₂₁ = 127.3373 d₂₁ = (Variable) r₂₂ = 32.2756 d₂₂ = 2.7500 n_(d12) = 1.60342 ν_(d12) = 38.03 r₂₃ = 145.1897 d₂₃ = 1.3750 n_(d13) = 1.77250 ν_(d13) = 49.60 r₂₄ = 16.7202 d₂₄ = (Variable) r₂₅ = 33.5170 d₂₅ = 7.5625 n_(d14) = 1.49700 ν_(d14) = 81.54 r₂₆ = −27.9038 d₂₆ = 0.2062 (Aspheric) r₂₇ = 69.1174 d₂₇ = 1.3750 n_(d15) = 1.84666 ν_(d15) = 23.78 r₂₈ = −19.6221 d₂₈ = 6.1875 n_(d16) = 1.49700 ν_(d16) = 81.54 r₂₉ = −57.6668 d₂₉ = (Variable) r₃₀ = = ∞ d₃₀ = 23.3750 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.3750 r₃₂ = ∞ d₃₂ = 2.2000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.3750 r₃₄ = ∞ d₃₄ = 1.0313 n_(d19) = 1.52300 ν_(d19) = 55.00 r₃₅ = ∞ d₃₅ = 3.2477 r₃₆ = ∞ Aspherical Coefficients 7th surface  K = 0  A₄ = −9.7269 × 10⁻⁶  A₆ = −1.1309 × 10⁻⁷  A₈ = 6.4969 × 10⁻¹⁰ A₁₀ = 0.0000 19th surface  K = 0  A₄ = −7.1713 × 10⁻⁶  A₆ = −1.9289 × 10⁻⁹  A₈ = −3.9414 × 10⁻¹¹ A₁₀ = 2.4197 × 10⁻¹³ 26th surface  K = 0  A₄ = −5.4190 × 10⁻⁷  A₆ = −2.7019 × 10⁻⁸  A₈ = −3.8924 × 10⁻¹¹ A₁₀ = 0.0000 Zooming Data (∞) W S T f (mm) 7.14571 18.85522 50.04974 F_(NO) 2.0047 2.3661 2.8509 ω (°) 38.44 15.98 6.16 d₅ 1.37500 21.94583 42.47373 d₁₃ 50.65754 14.25486 5.45806 d₁₆ 21.33520 12.38223 5.88901 d₂₁ 2.74731 5.18781 10.57000 d₂₄ 7.02907 7.05019 6.86418 d₂₉ 2.75000 9.01050 10.53508 Example 22  r₁ = 131.8770  d₁ = 2.6000  n_(d1) = 1.846662  ν_(d1) = 23.78  r₂ = 77.6142  d₂ = 0.2000  r₃ = 80.8510  d₃ = 6.3796  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 2977.8302  d₄ = 0.2000  r₅ = 67.0321  d₅ = 5.0727  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 266.3144  d₆ = (Variable)  r₇ = 1181.5043  d₇ = 1.7000  n_(d4) = 1.772502  ν_(d4) = 49.60  r₈ = 17.1175  d₈ = 8.6482  r₉ = 77.8867  d₉ = 0.2000  n_(d5) = 1.53508  ν_(d5) = 40.94 (Aspheric) r₁₀ = −246.1158 d₁₀ = 1.3000  n_(d6) = 1.77250  ν_(d6) = 49.60 r₁₁ = 430.0786 d₁₁ = 4.1745 r₁₂ = −24.0715 d₁₂ = 1.1790  n_(d7) = 1.48749  ν_(d7) = 70.23 r₁₃ = −346.5320 d₁₃ = 4.4844  n_(d8) = 1.84666  ν_(d8) = 23.78 r₁₄ = −42.2965 d₁₄ = (Variable) r₁₅ = −13.2198 d₁₅ = 1.3000  n_(d9) = 1.77250  ν_(d9) = 49.60 r₁₆ = −14.9920 d₁₆ = 1.0969 r₁₇ = ∞ (Stop) d₁₇ = (Variable) r₁₈ = 23.9865 d₁₈ = 5.3859 n_(d10) = 1.49700 ν_(d10) = 81.54 (Aspheric) r₁₉ = −62.7302 d₁₉ = 0.4217 r₂₀ = 65.9532 d₂₀ = 1.1010 n_(d11) = 4.80610 ν_(d11) = 40.92 r₂₁ = 18.5852 d₂₁ = 5.1465 n_(d12) = 1.49700 ν_(d12) = 81.54 r₂₂ = −44.8828 d₂₂ = (Variable) r₂₃ = 97.1974 d₂₃ = 0.9000 n_(d13) = 1.51633 ν_(d13) = 64.14 r₂₄ = 13.4425 d₂₄ = 3.0840 n_(d14) = 1.84666 ν_(d14) = 23.78 r₂₅ = 18.2242 d₂₅ = (Variable) r₂₆ = 22.8739 d₂₆ = 4.4524 n_(d15) = 4.49700 ν_(d15) = 81.54 (Aspheric) r₂₇ = −32.9476 d₂₇ = 0.1500 r₂₈ = 111.9927 d₂₈ = 3.9237 n_(d16) = 1.61800 ν_(d16) = 63.33 r₂₉ = −19.6931 d₂₉ = 1.0000 n_(d17) = 1.84666 ν_(d17) = 23.78 r₃₀ = −150.1546 d₃₀ = (Variable) r₃₁ = ∞ d₃₁ = 16.0000 n_(d18) = 1.51633 ν_(d18) = 64.14 r₃₂ = ∞ d₃₂ = 1.0000 r₃₃ = ∞ d₃₃ = 2.6000 n_(d19) = 1.54771 ν_(d19) = 62.84 r₃₄ = ∞ d₃₄ = 1.0000 r₃₅ = ∞ d₃₅ = 0.7500 n_(d20) = 1.51633 ν_(d20) = 64.14 r₃₆ = ∞ d₃₆ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 2.1755 × 10⁻⁵  A₆ = 7.8908 × 10⁻⁸  A₈ = −3.9978 × 10⁻¹⁰ A₁₀ = 1.3455 × 10⁻¹² 18th surface  K = 0  A₄ = −1.6485 × 10⁻⁵  A₆ = 1.0262 × 10⁻⁸  A₈ = −3.9805 × 10⁻¹⁰ A₁₀ = 3.5368 × 10⁻¹² 26th surface  K = 0  A₄ = −1.4825 × 10⁻⁵  A₆ = −5.9281 × 10⁻⁸  A₈ = 7.7542 × 10⁻¹⁰ A₁₀ = −4.4522 × 10⁻¹² Zooming Data (∞) W WS S ST T f (mm) 7.25994 12.99981 23.29962 41.72909 74.74765 F_(NO) 2.8000 3.3689 3.5000 3.5000 3.5000 ω (°) 38.50 . 13.16 . 4.16 d₆ 1.61417 10.64862 30.77400 47.23205 58.71613 d₁₄ 44.70529 23.26327 13.31755 6.20175 2.00079 d₁₇ 17.54504 10.44417 7.81832 5.52178 1.09606 d₂₂ 1.50000 7.82981 12.51540 16.74044 22.56134 d₂₅ 10.82401 10.71984 7.99123 5.55224 4.75986 d₃₀ 4.54790 5.42312 6.09200 6.60249 5.99969 Example 23  r₁ = 120.4727  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 73.3708  d₂ = 0.2000  r₃ = 76.1454  d₃ = 6.5370  n_(d2) = 1.49700  ν_(d2) = 81.54  r₄ = 2489.4366  d₄ = 0.2000  r₅ = 67.2263  d₅ = 5.1710  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 274.6988  d₆ = (Variable)  r₇ = 714.7087  d₇ = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 16.1327  d₈ = 8.7770  r₉ = −81.5087  d₉ = 1.5000  n_(d5) = 1.69350  ν_(d5) = 53.20 (Aspheric) r₁₀ = −1305.7058 d₁₀ = 4.0368 r₁₁ = −20.2734 d₁₁ = 1.1790  n_(d6) = 1.48749  ν_(d6) = 70.23 r₁₂ = −62.9405 d₁₂ = 4.8993  n_(d7) = 1.84666  ν_(d7) = 23.78 r₁₃ = −30.8273 d₁₃ = (Variable) r₁₄ = −15.4268 d₁₄ = 1.3000  n_(d8) = 1.77250  ν_(d8) = 49.60 r₁₅ = −18.4448 d₁₅ = 1.1025 r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 25.1535 d₁₇ = 5.5136  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −55.2846 d₁₈ = 1.5487 r₁₉ = 64.5304 d₁₉ = 1.1010 n_(d10) = 1.80610 r₂₀ = −18.9507 d₂₀ = 5.1163 n_(d11) = 1.49700 ν_(d11) = 81.54 r₂₁ = −43.1776 d₂₁ = (Variable) r₂₂ = −77.9341 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = 13.4277 d₂₃ = 3.4850 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₄ = 17.9962 d₂₄ = (Variable) r₂₅ = 21.5792 d₂₅ = 4.5936 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −34.1855 d₂₆ = 0.1500 r₂₇ = 300.7621 d₂₇ = 4.4791 n_(d15) = 4.61800 ν_(d15) = 63.33 r₂₈ = −17.4341 d₂₈ = −1.0000 n_(d16) = 1.84666 ν_(d16) = 23.78 r₂₉ = −75.6852 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₆ = ∞ d₃₅ = 1.2400 r₃₇ = ∞ Aspherical Coefficients 9th surface  K = 0  A₄ = 1.8629 × 10⁻⁵  A₆ = 6.9168 × 10⁻⁸  A₈ = −2.7327 × 10⁻¹⁰ A₁₀ = 1.2121 × 10⁻¹² 17th surface  K = 0  A₄ = −1.6089 × 10⁻⁵  A₆ = −2.0073 × 10⁻⁸  A₈ = 3.8142 × 10⁻¹⁰ A₁₀ = −2.1082 × 10⁻¹² 25th surface  K = 0  A₄ = −1.5463 × 10⁻⁵  A₆ = −2.6231 × 10⁻⁸  A₈ = 2.4043 × 10⁻¹⁰ A₁₀ = −9.6547 × 10⁻¹³ Zooming Data (∞) W S T f(mm) 7.25982 23.29910 74.74396 F_(NO) 2.8000 3.5000 3.5000 ω (°) 40.41 14.08 4.46 d₆ 1.59627 31.97645 59.22440 d₁₃ 44.75692 12.18599 2.03777 d₁₆ 17.39564 8.62546 1.04694 d₂₁ 1.58062 11.29335 21.65579 d₂₄ 9.55837 6.83300 4.68713 d₂₉ 4.66609 6.44892 5.81086 Example 24  r₁ = 128.7222  d₁ = 2.6000  n_(d1) = 4.84666  ν_(d1) = 23.78  r₂ = 76.5762  d₂ = 0.1990  r₃ = 79.6940  d₃ = 6.4626  n_(d2) = 4.49700  ν_(d2) = 81.54  r₄ = −2955.9452  d₄ = 0.2000  r₅ = 67.1272  d₅ = 5.0669  n_(d3) = 4.69680  ν_(d3) = 55.53  r₆ = 263.8928  d₆ = (Variable)  r₇ = 380.2582  d₇ = 1.7000  n_(d4) = 4.77250  ν_(d4) = 49.60  r₈ = 15.9616  d₈ = 8.7181  r₉ = −59.9828  d₉ = 1.5000  n_(d5) = 1.69350  ν_(d5) = 53.20 r₁₀ = −301.9443 d₁₀ = 3.8167 (Aspheric) r₁₁ = −20.5627 d₁₁ = 1.1790  n_(d6) = 4.48749  ν_(d6) = 70.23 r₁₂ = −59.0207 d₁₂ = 5.1126  n_(d7) = 4.84666  ν_(d7) = 23.78 r₁₃ = 30.2745 d₁₃ = (Variable) r₁₄ = 15.4364 d₁₄ = 1.3000  n_(d8) = 4.77250  ν_(d8) = 49.60 r₁₅ = −18.6107 d₁₅ = 1.1009 r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = 25.8357 d₁₇ = 5.4824  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −58.3524 d₁₈ = 1.9683 r₁₉ = 67.3450 d₁₉ = 1.1010 n_(d10) = 1.80610 ν_(d10) = 40.92 r₂₀ = 19.5738 d₂₀ = 5.1220 n_(d11) = 4.49700 ν_(d11) = 81.54 r₂₁ = 40.5031 d₂₁ = (Variable) r₂₂ = −94.9007 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = 13.4666 d₂₃ = 3.4715 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₄ = 17.9806 d₂₄ = (Variable) r₂₅ = 20.7610 d₂₅ = 4.5646 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −34.2142 d₂₆ = 0.1500 r₂₇ = 513.7109 d₂₇ = 4.4703 n_(d15) = 1.61800 ν_(d15) = 63.33 r₂₈ = −17.8110 d₂₈ = 1.0000 n_(d16) = 1.84666 ν_(d16) = 23.78 r₂₉ = −83.6823 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 16.0000 n_(d17) = 4.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.54771 ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₅ = 1.2400 r₃₆ = ∞ Aspherical Coefficients 10th surface  K = 0  A₄ = −1.7426 × 10⁻⁵  A₆ = −6.5228 × 10⁻⁸  A₈ = 2.7392 × 10⁻¹⁰ A₁₀ = −7.9412 × 10⁻¹³ 17th surface  K = 0  A₄ = −1.6148 × 10⁻⁵  A₆ = 6.2346 × 10⁻⁹  A₈ = −1.2987 × 10⁻¹⁰ A₁₀ = 1.1435 × 10⁻¹² 25th surface  K = 0  A₄ = −1.7043 × 10⁻⁶  A₆ = −3.2560 × 10⁻⁸  A₈ = 2.8184 × 10⁻¹⁰ A₁₀ = −1.6473 × 10⁻¹² Zooming Data (∞) W S T f (mm) 7.25999 23.30005 74.75174 F_(NO) 2.8000 3.5000 3.5000 ω (°) 38.46 13.17 4.17 d₆ 1.60767 32.04855 59.57895 d₁₃ 44.71134 12.27559 2.02865 d₁₆ 17.18153 8.38526 1.03922 d₂₁ 1.50000 11.41739 21.29066 d₂₄ 9.89355 6.80745 4.59258 d₂₉ 4.61028 6.57526 6.26289 Example 25  r₁ = 125.0583  d₁ = 2.6000  n_(d1) = 1.84666  ν_(d1) = 23.78  r₂ = 75.8265  _(d2) = 0.2052  r₃ = 78.8734  _(d3) = 6.6854  n_(d2) = 449700  ν_(d2) = 81.54  r₄ = −1567.5318  _(d4) = 0.2000  r₅ = 66.2728  _(d5) = 5.0118  n_(d3) = 1.69680  ν_(d3) = 55.53  r₆ = 235.6712  _(d6) = (Variable)  r₇ = 304.4445  _(d7) = 1.7000  n_(d4) = 1.77250  ν_(d4) = 49.60  r₈ = 16.9298  _(d8) = 8.3012  r₉ = −67.4212  _(d9) = 1.5000  n_(d5) = 1.77250  ν_(d5) = 49.60 r₁₀ = 58.4741 d₁₀ = 4.0559 r₁₁ = −33.1641 d₁₁ = 1.1790  n_(d6) = 1.48749  ν_(d6) = 70.23 r₁₂ = 123.4460 d₁₂ = 4.7343  n_(d7) = 1.68893  ν_(d7) = 31.07 r₁₃ = 32.8044 d₁₃ = (Variable) (Aspheric) r₁₄ = −13.3788 d₁₄ = 1.3000  n_(d8) = 1.77250  ν_(d8) = 49.60 r₁₅ = −14.1982 d₁₅ = 0.9997 r₁₆ = ∞ (Stop) d₁₆ = (Variable) r₁₇ = −21.1913 d₁₇ = 5.3343  n_(d9) = 1.49700  ν_(d9) = 81.54 (Aspheric) r₁₈ = −53.8005 d₁₈ = 0.3147 r₁₉ = 53.6050 d₁₉ = 1.1010 n_(d10) = 1.80610 ν_(d10) = 40.92 r₂₀ = 16.0840 d₂₀ = 5.1135 n_(d11) = 1.49700 ν_(d11) = 81.54 r₂₁ = −142.9938 d₂₁ = (Variable) r₂₂ = −42.8783 d₂₂ = 0.9000 n_(d12) = 1.51633 ν_(d12) = 64.14 r₂₃ = 13.9697 d₂₃ = 3.3288 n_(d13) = 1.84666 ν_(d13) = 23.78 r₂₄ = 21.2945 d₂₄ = (Variable) r₂₅ = 31.1501 d₂₅ = 4.3266 n_(d14) = 1.49700 ν_(d14) = 81.54 (Aspheric) r₂₆ = −23.5905 d₂₆ = 0.1500 r₂₇ = 911.4978 d₂₇ = 4.2792 n_(d15) = 1.61800 ν_(d15) = 63.33 r₂₈ = −15.3539 d₂₈ = 1.0000 n_(d16) = 4.84666 ν_(d16) = 23.78 r₂₉ = 50.5690 d₂₉ = (Variable) r₃₀ = ∞ d₃₀ = 16.0000 n_(d17) = 1.51633 ν_(d17) = 64.14 r₃₁ = ∞ d₃₁ = 1.0000 r₃₂ = ∞ d₃₂ = 2.6000 n_(d18) = 1.5477l ν_(d18) = 62.84 r₃₃ = ∞ d₃₃ = 1.0000 r₃₄ = ∞ d₃₄ = 0.7500 n_(d19) = 1.51633 ν_(d19) = 64.14 r₃₅ = ∞ d₃₆ = 1.2400 r₃₆ = ∞ Aspherical Coefficients 13th surface  K = 0  A₄ = −7.0043 × 10⁻⁶  A₆ = −5.4249 × 10⁻⁹  A₈ = 3.0262 × 10⁻¹² A₁₀ = 0.0000 17th surface  K = 0  A₄ = −1.8414 × 10⁻⁵  A₆ = −1.4788 × 10⁻⁸  A₈ = 5.9114 × 10⁻¹¹ A₁₀ = 0.0000 25th surface  K = 0  A₄ = −2.1192 × 10⁻⁵  A₆ = −1.3690 × 10⁻⁸  A₈ = 1.3573 × 10⁻¹⁰ A₁₀ = 0.0000 Zooming Data (∞) W S T f (mm) 2.8000 3.5000 3.5000 F_(NO) 7.26001 23.29997 74.74863 d₆ 1.71542 30.14291 58.15917 d₁₃ 44.90072 12.40034 2.55088 d₁₆ 19.05859 8.36633 0.99888 d₂₁ 1.50000 12.21200 22.72088 d₂₄ 8.15011 6.36382 5.19171 d₂₉ 4.65995 6.42650 4.45718

[0194] FIGS. 26 to 50 are aberration diagrams for Examples 1 to 25 upon focused on an object point at infinity. In these diagrams, SA, AS, DT and CC stand for spherical aberrations, astigmatisms, distortions and chromatic aberrations of magnification at the wide-angle end (a), the intermediate state (b) and the telephoto end of the system, respectively, with “FLY” representing an image height.

[0195] Enumerated below the values of conditions (1) to (14) in the respective examples. Condition Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 (1) 9.303 9.549 9.718 9.690 9.615 (2) 0.0280 0.0280 0.0280 −0.0019 −0.0019 (3) 5.104 5.097 5.172 5.302 5.296 (4) −0.331 −0.122 −0.068 −0.171 −0.175 (5) 0.581 0.570 0.557 0.594 0.610 (6) 10.296 10.296 10.296 10.296 10.296 (7) −0.287 −0.288 −0.269 −0.285 −0.281 (8) 0.058 0.182 0.151 0.068 −0.039 (9) −0.010 0.085 0.159 0.235 0.257 (10)  1.637 1.349 1.465 1.724 1.691 (11)  0.306 0.069 −0.139 −0.618 −0.545 (12)  2.846 2.846 2.891 2.846 2.956 (13)  2.800 2.800 2.800 2.800 2.800 (14)  2.984 3.206 3.124 3.060 3.066 Condition Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 (1) 9.257 9.346 9.311 9.123 9.260 (2) 0.0280 0.0280 0.0280 0.0280 0.0280 (3) 5.096 5.073 5.202 5.373 5.163 (4) −0.366 −0.508 −0.366 −0.750 −0.362 (5) 0.592 0.566 0.610 0.643 0.610 (6) 10.297 10.296 10.296 10.295 10.297 (7) −0.274 −0.297 −0.275 −0.326 −0.257 (8) 0.075 0.264 0.034 0.524 0.143 (9) 0.015 0.057 0.190 0.315 −0.034 (10)  1.744 2.059 1.668 2.280 1.622 (11)  0.223 −0.117 0.000 — 0.274 (12)  2.834 2.798 2.789 2.475 2.848 (13)  2.800 2.800 2.800 2.800 2.800 (14)  2.940 2.982 3.003 2.839 3.014 Condition Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ex. 15 (1) 9.978 9.887 9.754 10.142 9.704 (2) 0.0280 0.0280 0.0280 0.0280 0.0280 (3) 5.452 5.330 5.184 5.300 5.219 (4) −0.138 −0.156 −0.052 −0.096 −0.061 (5) 0.591 0.576 0.547 0.502 0.539 (6) 10.178 10.158 10.265 10.191 10.252 (7) −0.255 −0.261 −0.334 −0.315 −0.306 (8) 0.177 0.253 0.187 0.302 0.187 (9) 0.055 0.123 0.366 0.455 0.439 (10)  1.478 1.495 1.711 1.685 1.696 (11)  −0.078 −0.157 −0.444 −0.454 −0.566 (12)  2.784 2.334 2.954 2.818 3.041 (13)  2.800 2.800 2.800 2.800 2.800 (14)  3.225 3.122 3.289 3.030 2.986 Condition Ex. 16 Ex. 17 Ex. 18 Ex. 19 Ex. 20 (1) 9.110 9.595 9.707 7.465 7.644 (2) 0.0280 0.0280 0.0280 0.0280 0.0051 (3) 4.827 5.289 5.296 3.927 3.727 (4) −0.075 −0.149 −0.153 0.090 0.026 (5) 0.542 0.603 0.589 0.704 0.584 (6) 10.273 10.272 10.272 6.996 6.988 (7) −0.286 −0.270 −0.264 −0.294 −0.346 (8) 0.149 0.235 0.238 0.045 0.606 (9) 0.165 0.060 0.088 0.415 0.562 (10)  1.376 1.470 1.481 1.784 1.448 (11)  −0.139 −0.108 −0.120 — −0.736 (12)  2.834 2.525 2.525 3.454 3.665 (13)  2.800 2.800 2.800 2.048 2.029 (14)  2.817 3.103 3.122 3.078 2.989 Condition Ex. 21 Ex. 22 Ex. 23 Ex. 24 Ex. 25 (1) 7.409 9.448 8.780 9.391 9.275 (2) 0.0280 0.0280 0.0280 0.0280 0.0280 (3) 3.736 5.191 4.884 5.270 5.131 (4) 0.091 −0.337 −0.349 −0.358 −0.333 (5) 0.656 0.578 0.596 0.605 0.585 (6) 7.004 10.296 10.296 10.296 10.296 (7) −0.490 −0.291 −0.281 −0.280 −0.301 (8) −0.102 0.077 0.045 0.056 0.054 (9) 0.504 0.088 0.070 0.102 −0.011 (10)  1.404 1.495 1.386 1.467 1.642 (11)  −0.693 0.419 0.316 0.332 0.287 (12)  3.675 2.826 2.842 2.834 2.841 (13)  2.005 2.800 2.800 2.800 2.800 (14)  3.085 2.967 2.748 2.922 2.938

[0196] It is here noted that the resin layer provided on such lens elements as exemplified above is not in itself regarded as any lens element.

[0197] While various examples corresponding to the respective embodiments of the present invention have been given, it is appreciated that many other modifications thereto may be feasible without departing the scope of the invention described herein.

[0198] For instance, the second lens group G2 in each example may be composed of, in order from its object side, a negative lens element, a negative lens element, a negative lens element, a positive lens element and a positive lens element, as shown in FIG. 10.

[0199] The best arrangement for the third through sixth lens groups G3 through G6 is composed of six lens elements as shown in FIG. 19, or ten lens elements as shown in FIG. 19. Of course, it is noted that the number of lens elements in the rear lens groups, too, may be varied in the scope disclosed herein. For instance, it is possible to replace the positive single lens element on the object side of the fourth lens group G4 shown in FIG. 17 by a doublet lens component obtained by cementing together a positive lens element and a negative lens element; that is, it is possible to construct the third through sixth lens groups with 11 lens elements.

[0200] In what follows, the diagonal length L of the effective image pickup surface and the pixel interval a are now explained. FIG. 51 is illustrative of one exemplary pixel matrix for a given image pickup device. R (red), G (green) and B (blue) pixels are arranged in a mosaic pattern at a pixel interval a. By the term “effective image pickup surface” is intended an area within a photoelectric conversion surface on an image pickup device used for the reproduction of a phototaken image (e.g., for displaying an image on a personal computer or outputting an image to a printer). The effective image pickup surface is set at an area narrower than the overall photoelectric conversion surface of the image pickup device in correspondence to the performance of an optical system (an image circle wherein the performance of the optical system can be assured). The diagonal length L of the effective image pickup surface used herein is understood to mean the diagonal length of this effective image pickup surface. While the image pickup range used for image reproduction may be optionally varied, it is noted that when the zoom lens of the present invention is used for an image pickup device having such functions, there is a change in the diagonal length L of the effective image pickup surface thereof. In such a case, the diagonal length L of the effective image pickup surface according to the present invention is defined by the maximum value in the range allowed for L.

[0201]FIG. 52 is illustrative of the diagonal length of an effective image pickup surface in the case where a phototaking film is used instead of the image pickup device. When an image is formed on the phototaking film, the effective phototaking area is determined by the aperture of a viewing frame located just in front of the film surface. In this case, too, the shape of the viewing frame may be optionally varied. As in the case of FIG. 51, the diagonal length L of the effective phototaking surface according to the present invention is defined by the maximum value in the range allowed for L.

[0202] The inventive electronic image pickup device as explained above may be applied to phototaking devices wherein object images are formed through a zoom lens and then received on an image pickup device such as a CCD or a silver-salt film, especially digital cameras, video cameras, information processors represented by personal computers, telephone sets, convenient-to-carry portable telephones, etc., as typically explained below.

[0203] How the inventive zoom lens is incorporated in a phototaking optical system 41 of a digital camera is conceptually illustrated in FIGS. 53 through 55. FIG. 53 is a front perspective view of the outside shape of a digital camera 40, and FIG. 54 is a rear perspective view of the same. FIG. 55 is a sectional view illustrative of the construction of the digital camera 40. In this embodiment, the digital camera 40 comprises a phototaking optical system 41 having a phototaking optical path 42, a finder optical system 43 having a finder optical path 44, a shutter 45, a flash 46, a liquid crystal monitor 47, etc. As the shutter 45 attached onto the camera 40 is pressed down, an image is phototaken through the phototaking optical system 41 comprising the inventive zoom lens (roughly illustrated), e.g., the zoom lens system of Example 1. An object image formed through the phototaking optical system 41 is formed on the image pickup surface of a CCD 45 through an optical low-pass filter with an infrared cutting coat applied thereon. The object image received on the CCD 49 is displayed as an electronic image on the liquid crystal monitor 47 attached to the backside of the camera via processing means 51. If this processing means 51 is connected to recording means 52, then it is also possible to record the phototaken electronic image. It is here noted that the recording means 52 may be provided separately from the processing means 51 or, alternatively, may be constructed in such a way that images are written on floppy disks, memory cards, MOs or the like. If a silver-salt film is used instead of the CCD 49, it is then possible to construct a silver-salt camera.

[0204] Further, a finder objective optical system 53 is provided on the finder optical path 44. An object image formed by this finder objective optical system 53 is formed on a viewing frame 57 of an image erection Porro prism 55. In the rear of this Porro prism 55, there is disposed an eyepiece optical system 59 for guiding the erected image to the eyeball E of the observer. It is here noted that cover members 50 are provided on the incident sides of the phototaking optical system 45 and finder objective optical system 53, with a cover member 50 located on the exit side of the eyepiece optical system 59.

[0205] The thus constructed digital camera 40 can be achieved with high performance yet at low cost, because the phototaking optical system 41 is constructed of the inventive zoom lens which has a wide field angle and a high zoom ratio with improved aberrations and is fast with a back focus enough for receiving filters, etc.

[0206] In the FIG. 55 embodiment, plane-parallel plates are used as the cover members 50. However, it is acceptable to use powered lenses instead.

[0207] It is noted that the FIG. 55 embodiment is an example of the digital camera wherein the phototaking optical path 42 is located parallel with the finder optical path 44. If a prism for splitting the finder optical path is provided in association with an image pickup surface of the zoom lens system for the phototaking optical system 41, it is then possible to dispense with the finder objective optical system 53 and Porro prism 55 and, instead, provide a penta prism so as to guide a subject image to the eyeball E of an observer via the phototaking optical system 41.

[0208]FIG. 56(a) is a conceptual schematic illustrative of an objective optical system for a single-lens reflex camera, in which the inventive zoom lens is incorporated. In this case, too, the zoom lens system of Example 1 is used as an objective optical system 71. An image-formation light beam passing through this objective optical system 71 is split into a phototaking optical path and a finder optical path through a half-silvered mirror prism (a beam splitter or the like) 72. It is here preferable to use a quick-return mirror in place of the half-silvered mirror prism 72, because light quantity losses are avoidable. In the phototaking optical path, there are disposed a filter F such as a low-pass filter or an infrared cut filter and a CCD 73 to form an object image on an image pickup surface of the CCD 73 thorugh the filter F. The finder optical path is provided with a screen mat 74 on a primary image plane formed at a position conjugate to its image pickup surface. This primary image is reflected by a plane mirror 75, and then relayed as a secondary image via a relay optical system 76 where it is erected into an erected image. Finally, the secondary image is guided to the eyeball E of an observer via an eyepiece lens 77.

[0209] In the finder optical path portion shown in FIG. 56(a), the plane mirror 75 and relay optical system 76 may be replaced by a concave mirror prism 78 having positive power, as shown in FIG. 56(b). With this arrangement, it is possible to achieve some reduction in the number of parts and compactness. It is here noted that this concave mirror prism 78 may be composed of an entrance surface having power and an exit surface having power as well as a reflecting surface defined by not only a rotationally symmetric surface (such as a spherical or aspheric surface) but also a non-rotationally symmetric surface such as an anamorphic or free surface. By using a silver-salt film in place of the CCD 73, it is possible to obtain a silver-salt camera with the silver-salt film loaded therein.

[0210] FIGS. 57 to 59 are illustrative of a personal computer that is one exemplary information processor in which the inventive zoom lens is incorporated as an objective optical system. FIG. 57 is a front perspective view of an uncovered personal computer 300, FIG. 58 is a sectional view of a phototaking optical system 303 in the personal computer 300, and FIG. 59 is a side view of the FIG. 57 state. As can be seen from FIGS. 57 to 59, the personal computer 300 comprises a keyboard 301 via which an operator enters information therein from outside, information processing and recording means (not shown), a monitor 302 for displaying information to the operator and a phototakig optical system 303 for phototaking the image of the operator and the images of objects therearound. The monitor 302 used may be any one of a transmission type liquid crystal display device designed to be illuminated from its backside by a backlight (not shown), a reflection type liquid crystal display device wherein images are displayed by reflecting incoming light, a CRT display, and so on. As shown, the phototaking optical system 302 is built in the right upper portion of the monitor 302. However, it is noted that this phototaking optical system 302 may be located everywhere around the monitor 302 or the keyboard 301.

[0211] This phototaking optical system 303 comprises on a phototaking optical path 304 an objective lens 112 formed of the inventive zoom lens (roughly illustrated) and an image pickup device chip 162 for receiving an image. These are built in the personal computer 300.

[0212] An optical low-pass filter is additionally applied onto the image pickup device chip 162 to form a monolithic image pickup unit 160, which can be fitted in the rear end of a barrel 113 of the objective lens 112 in one-touch simple operation. Thus, any center or surface alignment of the objective lens 112 and image pickup device chip 162 can be dispensed with, so that these can be easily assembled together. It is noted that the barrel 113 is provided at the end with a cover glass 114 for protection of the objective lens 112 and the driving mechanism for the zoom lens in the barrel 113 is not shown.

[0213] An object image received on the image pickup device chip 162 is entered in the processing means of the personal computer 300 through a terminal 166, so that it is displayed as an electronic image on the monitor 302. As an example, an image 305 phototaken of the operator is depicted. It is also possible to display this image 305 on a remote display located on the other end of the computer via the processing means and via the Internet or a telephone.

[0214] FIGS. 60(a), 60(b) and 60(c) are illustrative of a telephone, especially a convenient-to-carry portable telephone that is one exemplary information processor in which the inventive zoom lens is incorporated as a phototaking optical system. FIG. 60(a) is a front view of a portable telephone 400, FIG. 60(b) is a side view thereof, and FIG. 60(c) is a sectional view of a phototaking optical system 405. As shown in FIGS. 60(a) to 60(c), the portable telephone 400 comprises a microphone portion 401 for entering operator's voice therein as information, a speaker portion 402 for producing the voice of an operator at the other end, an input dial 403 for allowing an operator to enter information therein, a monitor 404 for displaying the image of the operator or the image of the operator at the other end and information such as telephone numbers and processing means (not shown) for processing image information, communication information, input signals and so on. The monitor 404 used herein is a liquid crystal display device. It is noted that the positions where these parts are mounted are not limited to those illustrated. This phototaking optical system 405 comprises an objective lens 112 formed of the inventive zoom lens (roughly shown) disposed on a phototaking optical path 407 and an image pickup device chip 162 for receiving an object image. These are all built in the portable telephone 400.

[0215] An optical low-pass filter is additionally applied onto the image pickup device chip 162 to form a monolithic image pickup unit 160, which can be fitted in the rear end of a barrel 113 of the objective lens 112 in one-touch simple operation. Thus, any center or surface alignment of the objective lens 112 and image pickup device chip 162 can be dispensed with, so that these can be easily assembled together. It is noted that the barrel 113 is provided at the end with a cover glass 114 for protection of the objective lens 112 and the driving mechanism for the zoom lens in the barrel 113 is not shown.

[0216] An object image received on the image pickup device chip 162 is entered in the processing means (not shown) through a terminal 166, so that it is displayed as an electronic image on the monitor 402 and/or a monitor at the other end. As an example, an image 305 phototaken of the operator is depicted. To transmit images to the operator at the other end, the processing means includes a signal processing function of converting information on the object image received on the image pickup device chip 162 to transmittable signals.

[0217] As can be appreciated from the foregoing, the present invention can provide a wide-angle, high-zoom-ratio zoom lens system which is used for cameras having a small effective image pickup surface size such as a digital camera and compatible with TTL optical finders having a diagonal field angle of at least 70° at wide-angle ends and about 7 to 10 magnifications, and is fast as well, as expressed by an F-number of about 2.0 to 2.8 at the wide-angle end. 

What we claim is:
 1. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups, wherein a focal length f₁ of said first lens group and anomalous dispersion Δθ_(gF) of at least one positive lens element in said first lens group satisfy the following conditions: 6<f ₁ /L<20  (1)0.015<Δθ_(gF)<0.1  (2) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane, and the anomalous dispersion Δθ_(gF) of each medium (vitreous material) is defined by θ_(gF) =A _(gF) +B _(gF)·ν_(d)+Δθ_(gF) with the proviso that θ_(gF)=(n_(g)−n_(F))/(n_(F)−n_(c)) and ν_(d)=(n_(d)−1)/(n_(F)−n_(c)) wherein n_(d), n_(F), n_(c) and n_(g) are refractive indices with respect to d-line, F-line, C-line and g-line, respectively, and A_(g)F and B_(g)F are each a linear coefficient determined by two vitreous material types represented by glass code 511605 (available under the trade name of NSL7, Ohara Co., Ltd. with θ_(gF)=0.5436 and ν_(d)=60.49) and glass code 620363 (available under the trade name of PBM2, Ohara Co., Ltd. with θ_(gF)=0.5828 and ν_(d)=36.26); A_(gF) is 0.641462485 and B_(gF) is −0.001617829.
 2. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: 3<(Δz ₂ −Δz ₁)/L<9  (3) where the movement of each lens group toward said image side is assumed to be positive and L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 3. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: −1.0<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive.
 4. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups, wherein said first lens group moves toward said image side in a convex reciprocation locus and an amount of movement Δz_(1WM) of said first lens group from a wide angle end to an intermediate focal length of said zoom lens system, given by f_(M)(={square root}{square root over ( )}(f_(w)·f_(T))), is positive where f_(W) is a composite focal length of said zoom lens system when focused at said wide-angle end on an object point at infinity and f_(T) is a composite focal length of said zoom lens system when focused at said telephoto end on an object point at infinity, with the proviso that the movement of said first lens group lens toward said image side is assumed to be positive.
 5. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: −1.0<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive.
 6. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and a rear lens group having at least two movable subgroups, wherein the following conditions are satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: 3<(Δz ₂ −Δz ₁)/L<9  (3)−1.0<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive and L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 7. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following conditions are satisfied with respect to a ratio Δβ₂ (=β_(2T)/β_(2W)) where β_(2W) and β_(2T) are magnifications of said second lens group at said wide-angle end and said telephoto end, respectively, when said zoom lens system is focused on an object point at infinity and a zoom ratio y from said wide-angle end to said telephoto end of said zoom lens system: 0.3<log (Δβ₂)/(log (γ)<0.8  (5)5<γ<15  (6)
 8. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following condition is satisfied with respect to a composite magnification β_(rW) of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.6<β_(rW)<−0.1  (7)
 9. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein all said movable subgroups in said rear lens group have each at least one doublet component and the following condition is satisfied with respect to a composite magnification β_(rW) of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.6<β_(rW)<−0.1  (7)
 10. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein focusing is effected by any one of subgroups located nearer to an image side of said rear lens group than a positive subgroup of subgroups having negative magnification, said positive subgroup located nearest to an object side of said rear lens group, and the following condition is satisfied with respect to a magnification β_(RRW) of said positive subgroup located nearest to the image side of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.4<β_(RRW)<0.9  (8)
 11. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following conditions are satisfied with respect to an amount of movement Δ_(zRF) of a subgroup of said subgroups in said rear lens group, said subgroup having positive refracting power and located nearest to an object side of said rear lens group, from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δ_(zRR) of a positive subgroup located nearest to an image side of said rear lens group when said zoom lens system is focused on an object point at infinity: −0.4<Δ_(zRR)/Δ_(zRF)<0.8  (9)0.3<|Δ_(zRF) |/L<4.0  (10) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 12. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein said rear lens group comprises a subgroup having positive refracting power and negative magnification and a positive subgroup located nearest to an image side of said rear lens group which vary in relative positions thereof during zooming, said two positive subgroups have each at least one doublet component, at least one aspheric surface and at least one lens element formed of a vitreous material with ν>80 where ν is an Abbe constant.
 13. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein a subgroup located nearest to an image side of said rear lens group has negative refracting power.
 14. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein a subgroup located nearest to an image side of said rear lens group comprises one negative lens component.
 15. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein a subgroup located nearest to an image side of said rear lens group remains always fixed in the vicinity of an aperture stop and comprises one negative lens component.
 16. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein a focal length f₁ of said first lens group satisfies the following condition: 6<f ₁ /L<20  (1) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 17. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein a focal length f₁ of said first lens group and anomalous dispersion Δθ_(gF) of at least one positive lens element in said first lens group satisfy the following conditions: 6<f ₁ /L<20  (1)0.015<Δθ_(gF)<0.1  (2) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane, and the anomalous dispersion Δθ_(gF) of each medium (vitreous material) is defined by θ_(gF) =A _(gF) +B _(gF)·ν_(d)+Δθ_(gF) with the proviso that θ_(gF)=(n_(g)−n_(F))/(n_(F)−n_(c)) and ν_(d)=(n_(d)−1)/(n_(F)−n_(c)) wherein n_(d), n_(F), n_(c) and n_(g) are refractive indices with respect to d-line, F-line, C-line and g-line, respectively, and A_(gF) and B_(gF) are each a linear coefficient determined by two vitreous material types represented by glass code 511605 (available under the trade name of NSL7, Ohara Co., Ltd. with θ_(gF)=0.5436 and ν_(d)=60.49) and glass code 620363 (available under the trade name of PBM2, Ohara Co., Ltd. with θ_(gF)=0.5828 and ν_(d)=36.26); A_(gF) is 0.641462485 and B_(gF) is −0.001617829.
 18. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: 3<(Δz ₂ −Δz ₁)/L<9  (3) where the movement of each lens group toward said image side is assumed to be positive and L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 19. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: −1.0<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive.
 20. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein said first lens group moves toward said image side in a convex reciprocation locus and an amount of movement Δz_(1WM) of said first lens group from a wide angle end to an intermediate focal length of said zoom lens system, given by f_(M)(={square root}{square root over ( )}(f_(W)·f_(T))) where f_(W) is a composite focal length of said zoom lens system when focused at said wide-angle end on an object point at infinity and f_(T) is a composite focal length of said zoom lens system when focused at said telephoto end on an object point at infinity, with the proviso that the movement of said first lens group lens toward said image side is assumed to be positive.
 21. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein said first lens group moves toward said image side in a convex reciprocation locus and the following condition is satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: −1.0<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive.
 22. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power, and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein said first lens group moves toward said image side in a convex reciprocation locus and the following conditions are satisfied with respect to an amount of movement Δz₁ of said first lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δz₂ of said second lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: 3<(Δz ₂ −Δz ₁)/L<9  (3)−1<Δz ₁ /Δz ₂<0.5 where Δz ₂>0  (4) with the proviso that the movement of each lens group toward said image side is assumed to be positive and L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 23. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, and has negative refracting power and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein said second lens group comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and the following conditions are satisfied with respect to a ratio Δβ₂ (=β_(2T)/β_(2W)) where β_(2W) and β_(2T) are magnifications of said second lens group at said wide-angle end and said telephoto end, respectively, when said zoom lens system is focused on an object point at infinity and a zoom ratio γ from said wide-angle end to said telephoto end of said zoom lens system: 0.3<log (Δβ₂) /(log (γ)<0.8  (5)5<γ<15  (6)
 24. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein the following condition is satisfied with respect to a composite magnification β_(rW) of said rear lens groups when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.6<β_(rW)<−0.1  (7)
 25. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein all said movable subgroups in said rear lens group have each at least one doublet component and the following condition is satisfied with respect to a composite magnification β_(rW) of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.6<β_(rW)<−0.1  (7)
 26. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and at least two rear lens groups which are located subsequent to said second lens group and have a spacing variable during zooming, wherein focusing is effected by any one of subgroups located nearer to an image side of said rear lens group than a positive subgroup of subgroups having negative magnification, said positive subgroup located nearest to an object side of said rear lens group, and the following condition is satisfied with respect to a magnification β_(RRW) of said positive subgroup located nearest to the image side of said rear lens group when said zoom lens system is focused at said wide-angle end on an object point at infinity: −0.4<β_(RRW)<0.9  (8)
 27. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system, has negative refracting power and comprises at least three negative lens elements while a positive lens element is located nearest to said image side, or three negative lens elements located nearest to said object side while a positive lens element is located on said image side or a negative lens element while two positive lens elements are located nearest to said image side, with any one of surfaces in said second lens group being defined by an aspheric surface, and a rear lens group having at least two movable subgroups and comprising a total of 6 to 11 lens elements inclusive, wherein the following conditions are satisfied with respect to an amount of movement Δ_(zRF) of a subgroup of said subgroups in said rear lens group, said subgroup having positive refracting power and located nearest to an object side of said rear lens group, from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity and an amount of movement Δ_(zRR) of a positive subgroup located nearest to an image side of said rear lens group when said zoom lens system is focused on an object point at infinity: −0.4<Δ_(zRR)/Δ_(zRF)<0.8  (9)0.3<|Δ_(zRF) |/L<4.0  (10) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 28. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having a plurality of subgroups, wherein said rear lens group comprises a subgroup having positive refracting power and negative magnification and a positive subgroup located nearest to an image side of said rear lens group, said two positive subgroups varying in relative positions thereof during zooming with a negative subgroup located therebetween, and having each at least one doublet component, at least one aspheric surface and at least one lens element formed of a vitreous material with ν>80 (ν is an Abbe constant).
 29. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system and has positive refracting power, a second lens group which moves toward an image side of said zoom lens system during zooming from a wide-angle end to a telephoto end of said zoom lens system and has negative refracting power and a rear lens group having a plurality of subgroups, wherein the following conditions are satisfied with respect to an amount of movement Δ_(zRF) of a subgroup in said rear lens group from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity, said subgroup having positive refracting power and negative magnification and located nearest to an image side of said rear lens group and an amount of movement Δ_(zRR) of a positive subgroup located nearest to an image side of said rear lens group when said zoom lens system is focused on an object point at infinity, said rear lens group has between said two positive subgroups a negative subgroup varying in a position relative thereto during zooming, and the following condition is satisfied with respect to an amount of movement Δ_(zRN) of said negative subgroup from said wide-angle end to said telephoto end when said zoom lens system is focused on an object point at infinity: −0.4<Δ_(zRR)/Δ_(zRf)<0.8  (9)0.3<|Δ_(zRF) |/L<4.0  (10)−2<Δ_(zRN) /L<1  (11) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 30. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and having negative refracting power and a rear lens group which is located subsequent to said second lens group and at least three spacings variable during zooming, wherein a subgroup located nearest to an object side of said rear lens group has negative refracting power.
 31. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and having negative refracting power and a rear lens group which is located subsequent to said second lens group and at least three spacings variable during zooming, wherein a subgroup located nearest to an object side of said rear lens group comprises one negative lens component.
 32. A zoom lens system comprising, in order from an object side thereof, a first lens group which is movable along an optical axis of said zoom lens system during zooming and having positive refracting power, a second lens group which moves toward an image side of said zoom lens system along said optical axis during zooming from a wide-angle end to a telephoto end of said zoom lens system and having negative refracting power and a rear lens group which is located subsequent to said second lens group and at least three spacings variable during zooming, wherein a subgroup located nearest to an object side of said rear lens group remains always fixed in the vicinity of an aperture stop and comprises one negative lens component.
 33. The zoom lens system according to claim 1, wherein said subgroup located nearest to said object side of said rear lens group has negative magnification.
 34. The zoom lens system according to claim 1, which comprises a zoom zone including a field angle 2ω=70° at which phototaking is possible.
 35. The zoom lens system according to claim 1, wherein the following condition is satisfied with respect to a back focus F_(BW) (as calculated on an air basis) of said zoom lens system when focused at said wide-angle end on an object point at infinity: 2.0<F _(BW) /f _(W)<5.0  (12) where f_(W) is a composite focal length of said zoom lens system when focused at said wide-angle end on an object point at infinity.
 36. The zoom lens system according to claim 1, wherein the following condition is satisfied with respect to a minimum F-number F_(W) of said zoom lens system when focused at said wide-angle end on an object point at infinity: 1.4<F _(W)<3.5  (13)
 37. The zoom lens system according to claim 1, wherein the following condition is satisfied with respect to an entrance pupil position ENP of said zoom lens system at said wide-angle end: 2<ENP/L<5  (14) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 38. The zoom lens system according to claim 1, which is used as an image-formation optical system for a phototaking system (a camera, a video movie, etc.) having an image pickup device having a pixel interval a given by 1.0×10⁻⁴ ×L<a<6.0×10⁻⁴ ×L  (mm) where L is a diagonal length of an effective image pickup surface located in the vicinity of an image-formation plane.
 39. An image pickup system comprising an image pickup device located in the vicinity of an image-formation plane of a zoom lens system as recited in any one of claims 1 to
 32. 40. The image pickup system according to claim 40, wherein an electronic image pickup device is used as said image pickup device and a low-pass filter is located between said zoom lens system and said electronic image pickup device.
 41. The image pickup system according to claim 40, wherein between said zoom lens system and said electronic image pickup device there is located an optical element for splitting an observation optical path. 